ACS Applied Bio Materials最新文献

Wound infections represent a significant global healthcare burden, often complicating healing processes and leading to increased morbidity. These infections vary in type, ranging from acute to chronic, surgical site infections, and pressure ulcers, each presenting distinct pathological and microbiological profiles. The primary causative agents include Gram-positive bacteria such as Staphylococcus aureus and Streptococcus pyogenes as well as Gram-negative pathogens such as Pseudomonas aeruginosa and Escherichia coli. Conventional treatment modalities largely rely on systemic or topical antibiotics, debridement of the wound, and antiseptics. However, rising antimicrobial resistance, slow tissue regeneration, and recurrent infections limit the efficacy of these approaches. Recent advances in nanotechnology- and biopolymer-based materials have enhanced wound care options. Biopolymers such as chitosan, alginate, and collagen are valued for their biocompatibility and biodegradability. Chitosan uniquely offers inherent antimicrobial activity, while collagen, alginate, and agarose mainly function as biocompatible scaffolds or drug delivery systems without significant antibacterial properties. When combined with metal nanoparticles, particularly silver, zinc oxide, and gold, these composites exhibit enhanced antibacterial activity, anti-inflammatory effects, and improved wound healing dynamics. Such nanocomposites can be engineered into films, hydrogels, and scaffolds that facilitate moisture retention, controlled drug release, and tissue regeneration, while minimizing cytotoxicity. The integration of nanotechnology with biopolymer science represents a paradigm shift in wound management strategies. This multidisciplinary approach not only addresses the limitations of conventional therapies but also offers tailored, responsive, and effective wound healing platforms. Continued research into the synergistic effects of nanoparticles and natural polymers is essential to fully realize their clinical potential. Ultimately, these innovations could transform wound care, offering patients faster recovery, reduced infection rates, and an improved quality of life. Additionally, hybrid nanocomposites such as hydroxyapatite-based systems have shown enhanced bioactive properties.

Melanoma is a rare but highly aggressive form of skin cancer that can rapidly metastasize, leading to a significant mortality rate. A main challenge in chemotherapy is the lack of selectivity in drug delivery to tumor sites, which affects both tumor and healthy tissues. Developing drug delivery systems (DDS) capable of preferentially interacting with transporters expressed on cancer cells may help address this issue. Carbon dots (CDs) have emerged as promising tools for the advancement of DDS due to their distinctive fluorescent characteristics, good water solubility, biocompatibility, and straightforward fabrication. In this work, CDs were synthesized via a facile method and conjugated with tryptophan (Trp) to evaluate their potential application as a DDS in melanoma. The fabricated CDs were characterized for their size, surface charge, optical properties, functional groups, and elemental analysis. LAT1 expression was examined by immunofluorescence, confirming higher levels in SK-MEL-2 melanoma cells compared to HK-2 normal kidney cells. Biocompatibility was established before conjugating CDs with tryptophan (Trp), ditryptophan (di-Trp), and tritryptophan (tri-Trp) and assessing their size, functional groups, and optical characteristics. Cellular uptake studies showed preferential uptake of Trp-conjugated CDs in SK-MEL-2 cells over HK-2 cells, indicating that tri-Trp-CDs exhibited the highest uptake. Molecular dynamics simulations suggested potential CDs-LAT1 interactions via van der Waals and electrostatic interactions. Trp-conjugated CDs were biocompatible with both SK-MEL-2 and HK-2 cells and could be electrostatically loaded with doxorubicin (DOX), exhibiting enhanced cytotoxicity against SK-MEL-2 cells compared to DOX alone. A trend toward greater selectivity for SK-MEL-2 cells over normal cells was observed, with tri-Trp/DOX showing the most pronounced effect, possibly reflecting LAT1-1 mediated uptake. These findings suggest that Trp-modified CDs may serve as promising DDS candidates for melanoma treatment.

The development of sustainable, soft, and recyclable materials for skin-integrated electronics is critical for advancing wearable health monitoring while minimizing electronic waste. Here, chitosan–agarose-based hydrogels integrated with poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) are fabricated as recyclable, biocompatible, and thermoresponsive materials for flexible temperature sensors. The hydrogels are synthesized using a green and easy process, forming interpenetrated dual networks that exhibit high water content, mechanical compliance, and enhanced electroconductivity. Morphological analysis reveals highly porous interconnected structures, while Fourier transform infrared spectroscopy confirms the successful incorporation of PEDOT:PSS. The hydrogels display high swelling capacity, tunable mechanical properties within the physiological range of human skin, and enhanced electrochemical performance. The temperature-sensing capability of the hydrogels demonstrates a negative temperature coefficient of resistance (TCR) of up to −1.5% °C^–1, outperforming similar hydrogel-based sensors while maintaining stability over repeated thermal cycles. Importantly, the hydrogels can be disassembled, reprocessed, and reused for multiple sensing cycles without significant loss of performance, demonstrating true recyclability and supporting circular material use in soft electronics. The convergence of natural biopolymers with conducting polymers within these hydrogels provides a promising platform for developing eco-friendly, flexible bioelectronic devices, aligning with the requirements of sustainable materials science while addressing the need for high-performance, soft temperature sensors for wearable healthcare applications.

Efficient oral delivery and sustained viability of probiotics remain significant obstacles to the clinical translation of live biotherapeutics. Therefore, in this study, we developed self-assembling keratin hydrogels derived from feather waste using a disulfide shuffling strategy for probiotic encapsulation. This cost-effective and scalable approach substantially improved the gastrointestinal tolerance and oral bioavailability of multiple probiotics, including Escherichia coli Nissle 1917 (EcN), Bacillus licheniformis, Lactococcus lactis, and Bifidobacterium bifidum. To achieve site-specific release in the intestinal tract, EcN was engineered to express keratinase (EcNker), enabling hydrogel degradation in the gut. In dextran sulfate sodium-induced colitis model mice, hydrogel-encapsulated EcNker exhibited markedly superior therapeutic efficacy over unencapsulated probiotics, as indicated by the amelioration of clinical symptoms, restoration of colon histology, attenuation of intestinal apoptosis, and normalization of inflammatory cytokine profiles. Mechanistically, hydrogel-encapsulated EcNker treatment restored the gut barrier integrity by upregulating the tight junction protein levels, modulating gut microbiota by increasing the number of beneficial genera, and enhancing short-chain fatty acid production. Collectively, our findings highlight the potential of keratin hydrogels as universal biocompatible and efficient delivery platforms for orally engineered probiotics to treat colonic colitis and other diseases.

Over the years, 3D printing has become a multidisciplinary research hotspot and state-of-the-art technology for developing bioinspired structures with intricate geometry, mechanical robustness and verified designs. However, the extrusion complexity of thermoplastic elastomeric filaments makes it challenging to design complex shapes in filament-based extrusion 3D printing. Herein, the paucity of low-modulus ethylene-co-vinyl acetate (EVA) polymer for the fabrication of bone tissue mimetic scaffolds was addressed by compounding with hydroxyapatite (HAP) and the effects of HAP incorporation on extrudability, printability, mechanical properties and osteoblast–material interactions were studied. The systematic optimization of printability and printing parameters enabled successful 3D printing of composite scaffolds with controlled deposition, pore geometry and architecture using a pellet-extrusion 3D printer. The die swell, unstable extrudate deposition and warpage of the EVA polymer melt subsided upon HAP addition. Confocal Raman microscopy and scanning electron microscopy (SEM) confirmed the uniform dispersion of HAP in EVA matrix, necessary to yield stable extrusion of the polymer melt. Dynamic mechanical analysis (DMA) revealed a 5-fold increase in storage modulus as well as a shift in Tg of the composites from −13°C to −9.8°C for 40 vol % HAP, confirming the possible polymer-HAP interactions. Biocompatibility studies demonstrated robust viability, proliferation and cellular integrity, especially in scaffolds with 40 vol % HAP. Moreover, F-actin staining of MG-63 cells revealed expanded cell pseudopods distributed evenly across the scaffold surface with a polygonal spreading pattern, confirming the cell adhesion and proliferation conducive for osteogenesis on the composite scaffolds. Osteogenic differentiation, as evidenced by ALP activity and Alizarin red S staining, indicated statistically higher levels of osteogenic-related factors and mineralization in composite scaffolds relative to neat EVA. These primary findings collectively support that the EVA-HAP composite, especially with 40 vol % HAP loading, provides a suitable microenvironment for osteoblast activities and is expected to promote bone tissue formation.

Biomaterials hold great potential for the development of green electronics owing to their biocompatibility, biodegradability, and sustainability. With an immense amount of data generation and digitization, the urge for emerging memory devices has also spiked in recent times. Herein, we present an environment-friendly memory device comprising a nanocellulose/zinc oxide (ZnO) bilayer for stable resistive memory application, where silver (Ag) and fluorine-doped tin oxide (FTO) are used as the active and counter electrodes, respectively. Steady bipolar resistive memory characteristics could be observed with the current ON/OFF ratio > 10² and at a low switching voltage (less than ±0.4 V). The switching mechanism could be hypothesized with the Ag⁺ migration from the active electrode, which could be controlled by the introduction of a ZnO layer resulting in an interfacial electric field. The Ag/nanocellulose/ZnO/FTO device could also retain the resistive memory features after water treatment and 30 days of stowing in vacuum.

Cancer remains a leading cause of global mortality, underscoring the urgent need for safe, effective, and innovative therapeutic strategies. Nanotechnology, particularly nanogels, offers promising opportunities for cancer treatment. Natural flavonoids exhibit significant antitumor activity, but their poor water solubility and low bioavailability limit clinical application. Natural polysaccharides overcome these challenges through excellent biocompatibility, biological activity, and potential as nanomaterial scaffolds. Herein, a glutathione (GSH)-responsive disulfide bond cross-linker, DBHD, was successfully synthesized. Using DBHD, a redox-responsive nanogel system (QFD NGs) was constructed through covalent cross-linking of the natural macromolecule Fomitopsis officinalis polysaccharide (FOBP) and encapsulation of quercetin (QU). In vitro release assays demonstrated that QFD NGs rapidly released drugs under high GSH concentrations characteristic of the tumor microenvironment. Cell culture and zebrafish model experiments confirmed that QFD NGs efficiently inhibited tumor cell proliferation, invasion, and metastasis while inducing apoptosis. Additionally, QFD NGs demonstrated remarkable immunomodulatory activity by activating macrophages, promoting nitric oxide (NO) production, and upregulating costimulatory molecules (CD40, CD80, CD86), as well as MHC-II expression. This study introduces QFD NGs as a synergistic therapeutic platform combining chemotherapy and immunotherapy, offering a promising strategy for developing efficient, low-toxicity cancer treatments based on natural products.

The interaction of microbial consortia within biofilms leads to emergent properties such as high resistance to environmental fluctuations, efficient biocatalytic performance, and stable metabolic states. However, the mechanisms governing these interactions are hard to capture and are not fully understood. Agarose has proven to be a good mimic of the extracellular polymeric substance, which is the polymeric matrix supporting the connectivity of microbial consortia within biofilms. We aimed at modifying polymeric agarose to generate in situ sensing functionalities for monitoring metabolic states within the encapsulated microbial consortia. For that, agarose was end-on chemically modified to couple the pH-responsive FAM dye. After reconstitution of hydrogels out of the functionalized agarose, a stable covalent coupling of the dyes was demonstrated using fluorescence recovery after photobleaching, showing a reduction of free FAM dye from 51% using common water washing procedures to no measurable amount of free dye using our washing procedure. Furthermore, the ability to monitor relevant pH ranges between 6 and 8 was experimentally demonstrated in the hydrogels by laser scanning microscopy. Furthermore, the application of the functional agarose hydrogels was shown in cell cultures with chemoheterotrophic and phototrophic microbial strains (Pseudomonas taiwanensis and Synechocystis sp.). The monitoring of pH changes of microbial consortia dependent on their metabolic performance over up to 3 days was proven, paving the road to the utilization of such functional agarose matrices to study metabolic interactions in complex microbial consortia.

In this research study, a series of four acyl thiourea ligands and their corresponding rhodium(III) pentamethylcyclopentadienyl complexes, designated as Rh1, Rh2, Rh3, and Rh4, were successfully used to explore their suitability for a biological macromolecule, i.e., α-chymotrypsin (α-CT). Through meticulous analysis of the spectroscopic data, it was convincingly established that the acyl thiourea ligands served as neutral and monodentate ligands in their interaction with the Rh(III) ions. Specifically, the spectroscopic evidence confirmed that the sulfur (S) atoms within the acyl thiourea ligands formed coordinated bonds with the Rh(III) ions. This crucial finding elucidates the specific coordination mode and binding interactions between the ligands and the central Rh(III) metal ion, which have seldom been investigated. Importantly, various biophysical studies and enzymatic activity results suggested that the structural stability of α-CT was maintained in these Rh(III) complexes. Interestingly, the metal complexes enhanced the thermal stability of α-CT, as indicated by an increase in the transition temperature (T_m) of α-CT. This study unveils the promising role of Rh(III) metal complexes in the stabilization and activation of the biological macromolecule, which further holds potential in industrial and biomedical applications.

Developing cost-effective and highly active nanozymes compatible with accessible biosensing platforms remains a critical challenge for robust diagnostics. This study presents a facile and scalable method for synthesizing teicoplanin-stabilized platinum nanoparticles (Pt@Tei), utilizing the glycopeptide antibiotic teicoplanin as a unique stabilizer. Pt@Tei nanozymes exhibit potent peroxidase-mimetic activity, efficiently catalyzing the oxidation of chromogenic substrates (like 3,3′,5,5′-tetramethylbenzidine (TMB)) in the presence of H₂O₂. The results indicate that the catalytic activity of Pt@Tei remained almost unchanged for at least 15 days, demonstrating the superiority of teicoplanin as a stabilizer. To demonstrate its application, we developed a sensitive smartphone-based colorimetric glucose biosensor. This assay integrates Pt@Tei nanozymes with glucose oxidase (GO_x) to initiate an enzymatic cascade: Glucose is first converted to gluconic acid, generating H₂O₂. The Pt@Tei then catalyzes the H₂O₂-dependent oxidation of TMB, producing a measurable color change. Key experimental conditions were optimized, achieving optimal performance at 37 °C and pH 5.0. Under these conditions, the Pt@Tei nanozyme demonstrated a limit of detection (LOD) for H₂O₂ of 0.177 μM. This system was further integrated into a paper-based analytical device (PAD). The PAD yielded a strong, quantifiable colorimetric signal in the red channel, directly proportional to the glucose concentration over the range of 0–10 mM (R² = 0.993), with a low glucose LOD of 0.385 mM. The platform exhibited excellent selectivity against common interfering analytes and high reproducibility (relative standard deviation (RSD) ≤ 4%). Critically, validation with goat serum samples showed strong agreement with a commercial meter and excellent spike recovery (98–102%), confirming their practical applicability. This work highlights teicoplanin as an effective stabilizer for nanozyme development and establishes a promising, accessible point-of-care platform for glucose monitoring.