ACS Applied Bio Materials最新文献

The detection and dynamic monitoring of intracellular NAD(P)H concentrations are crucial for comprehending cellular metabolism, redox biology, and their roles in various physiological and pathological processes. To address this need, we introduce sensor A, a near-infrared ratiometric fluorescent sensor for real-time, quantitative imaging of NAD(P)H fluctuations in live cells. Sensor A combines a 3-quinolinium electron-deficient acceptor with a near-infrared rhodamine dye, offering high sensitivity and specificity for NAD(P)H with superior photophysical properties. In its unbound state, sensor A emits strongly at 650 nm and weakly at 465 nm upon 400 nm excitation. Upon binding to NAD(P)H, it shows a fluorescence increase at 465 nm and a decrease at 650 nm, enabling accurate ratiometric measurements. Sensor A also exhibits ratiometric upconversion fluorescence when excited at 800 or 810 nm, offering additional flexibility for different experimental setups. The sensor's response relies on the reduction of the 3-quinolinium acceptor by NAD(P)H, forming a 1,4-dihydroquinoline donor that enhances fluorescence at 465 nm and quenches the near-infrared emission at 650 nm through photoinduced electron transfer. This mechanism ensures high sensitivity and reliable quantification of NAD(P)H levels while minimizing interference from sensor concentration, excitation intensity, or environmental factors. Sensor A was validated in HeLa and MD-MB453 cells under various metabolic and pharmacological conditions, including glucose and maltose stimulation and treatments with chemotherapeutic agents. Co-localization with mitochondrial-specific dyes confirmed its mitochondrial targeting, enabling precise tracking of NAD(P)H fluctuations. In vivo imaging of Drosophila larvae under nutrient starvation or chemotherapeutic exposure revealed dose-dependent fluorescence responses, highlighting its potential for tracking NAD(P)H changes in live organisms. Sensor A represents a significant advancement in NAD(P)H imaging, providing a powerful tool for exploring cellular metabolism and redox biology in biomedical research.

Excessive use of chemical pesticides in farming has raised great concerns about food safety because of pesticide contamination in fruits and vegetables. Pesticides like chlorpyrifos have been linked to liver and kidney damage, respiratory problems, neurological disorders, developmental delays, endocrine disruption, and gut microbiota alterations. Moreover, rapid spoilage of perishable agricultural produce like fruits and vegetables contributes to huge postharvest losses every year and worsens food security. This study addresses these two concerns by developing an eco-friendly coating made of guar gum, vinegar, and tamarind pulp. The coating's antibacterial properties were tested against Escherichia coli and Staphylococcus aureus, while its antioxidant capacity was measured using DPPH assay. The effectiveness of the coating in reducing pesticide residues was analyzed through high-performance liquid chromatography (HPLC). The results showed antibacterial activity and high antioxidant capacity, with free radical scavenging activity of 61.33% for vinegar, 47.81% for tamarind, and 49.9% for the composite. HPLC analysis showed that the coating reduced chlorpyrifos residues on treated produce compared to the control. Moreover, the coating extended the shelf life of perishable fruits and vegetables by reducing moisture loss and microbial growth. These findings suggest that the tamarind-vinegar-guar gum composite is a sustainable solution to pesticide contamination and postharvest losses and a significant contribution to food safety and security.

It is highly desirable yet significantly challenging to fabricate an injectable, self-healing, controlled-release wound dressing that is responsive to the alkaline pH of the wounds. Herein, we propose a facile approach to prepare pH-responsive chitosan-oxidized carboxymethyl cellulose (CS-o-CMC) hydrogel constructs in which gelation was achieved via electrostatic and Schiff base formation. Importantly, the Schiff base was formed in acidic medium and the final pH of pregel solution was intrinsically raised to 7.0-7.4 due to the cross-linking by β-glycerol phosphate. The self-healing behavior of the hydrogel was an enthalpy-driven process and efficient in alkaline compared to acidic pH. The pH responsiveness offered a controlled release of lauric acid (LA) from CS-o-CMC/LA hydrogel and regulated the M2 polarization. Overall, reduction in inflammation led to rapid vascularization, reepithelialization, and significantly accelerated wound healing in rats. Our findings demonstrate a promising strategy for developing injectable, immunomodulatory wound dressings tailored to the challenging environment of wounds.

Mesenchymal stem cells (MSCs) have demonstrated promising therapeutic potential across a wide range of diseases including (multi) organ injury in neonates. Despite the reported preclinical successes of MSC therapy, a major challenge in their clinical translation is a limited understanding of their biodistribution after administration. This knowledge gap needs to be addressed to allow clinical implementation. Accordingly, in this study, we propose that silica-coated gold nanoparticles (AuMS) are a promising tool for in vivo MSC tracing. This study explores the use of AuMS for both qualitative and quantitative MSC tracking in vivo after intravenous (I.V.) administration in a translational ovine model of preterm birth. Additionally, we assess the impact of AuMS labeling on the immunomodulatory functions of MSC, which play an important role in the therapeutic potency of these cells. Quantitative and qualitative assessment of AuMS-labeled MSC was performed in vivo using fluorescent microscopy and inductively coupled plasma mass spectrometry (ICP-MS), respectively. AuMS localization in the liver, spleen, and lung was demonstrated. In vitro studies showed that AuMS cellular uptake occurs within 6 h and remains internalized up to 72 h. Labeled MSC maintained their immune phenotype and did not alter their immunomodulatory capacity and proliferation abilities. Overall, we demonstrate that AuMS is a promising, biocompatible nanoprobe for MSC tracing up to 72 h post-I.V. administration.

Targeting Prostate Specific Membrane Antigen (PSMA) has proven highly useful and beneficial for prostate cancer (PCa) theranostics. However, patients with advanced metastatic castration-resistant prostate cancer (mCRPC) lack optimal PSMA expression resulting in poor specificity. To address this limitation, combination targeting is gaining popularity by synergistically boosting the theranostic efficacy. Herein, we thoroughly reviewed the most recent development of drug formulation for PCa theranostics by targeting both PSMA and Fibroblast Activation Protein (FAP). FAP is known to overexpress in cancer-associated fibroblasts (CAFs) within the tumor microenvironment (TME). It has been extensively studied as an effective target for the identification and treatment of a variety of cancer phenotypes. Along with the advantages and current updates on combination targeting of PSMA and FAP, this Review thoroughly discussed the expression patterns of PSMA and FAP in various cancer phenotypes, as well as their role in tumor growth, invasion, and metastasis, which is of great interest in the design and development of prostate cancer theranostics.

Magnetic drug targeting requires particles to move through the complex viscoelastic environments of tissues and biological fluids. However, these environments often inhibit particle motion, making it difficult for magnetically guided particles to reach their intended targets. Magnetic microrods are easy to grow and manipulate, but experience significant hindrance to transport in complex, tortuous, tissue-like environments. Simple magnetic force translation ("pulling" or "pushing") is often insufficient or inefficient for long-range transport of microrods through such environments. Designing microrods capable of rotating while being pulled with a magnetic force may enable rods to overcome hindrances to transport. We present microrods with orthogonally magnetized segments, actuated by simultaneous magnetic force and magnetic torque. By simultaneously pulling and rotating our rods we create smooth-surfaced magnetic drilling microrods (MDMRs) capable of enhanced motion through protein-dense biopolymers. We model magnetic force and torque on MDMRs, characterize MDMR dynamics during transport, and demonstrate enhanced MDMR transport through protein-dense matrices in vitro.

Sodium carboxymethylcellulose (CMC) is a biocompatible and biodegradable derivative of cellulose, making it a promising material for biomedical applications. However, its poor stability in aqueous environments has significantly limited its use in long-term biomedical devices. Here, we present for the first time a simple and controllable method to enhance the wet stability of CMC coatings by cross-linking of CMC and polydopamine (PDA) and self-polymerization of PDA for widespread applications in biomedical devices. A series of CMC/PDA coatings were fabricated on the initial PDA layers by using dip coating and subsequently heated at 200 °C. The performance of the CMC/PDA coatings and their chemical and structural stability in aqueous media have been systematically analyzed, and the mechanisms underpinning their robust performance have been revealed. FITR, X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC) results showed that CMC/PDA coatings involved amidation and esterification reactions as well as self-polymerization of PDA. Degradation studies in phosphate-buffered saline (PBS) solution at 37 °C indicated degradation via ester and amide bond cleavage, with the stability of CMC/PDA coatings surpassing that of individual PDA and CMC coatings over a 30-day immersion period. The CMC/PDA coating with a CMC concentration of 15 mg/mL exhibited the highest adhesion strength in an aqueous environment, which was attributed to the high cross-linking of CMC and PDA, as well as the intrinsic stability of PDA. The CMC/PDA coatings demonstrated favorable viability, growth, and proliferation of endothelial cells. The stable and biocompatible biocellulose coatings can be easily applied from aqueous solutions onto almost any type of solid metal and ceramic material, providing a promising dimension for surface engineering of vascular scaffolds and tissue engineering constructs.

The treatment of critically ill patients has made great strides in the past few decades due to the rapid development of indwelling medical devices. Despite immense advancements in the design of these devices, indwelling medical device-associated infections and thrombosis are two major clinical problems that may lead to device failure and compromise clinical outcomes. Antibiotics are the current treatment choice for these infections; however, the global emergence of antibiotic-resistance and their biofilm formation abilities complicate the management of such infections. Moreover, systemic administration of anticoagulants has been used to counter medical device-induced thrombosis, but a range of serious adverse effects associated with all types of available anticoagulants entails exploring alternative options to counter device-associated thrombosis. In this study, bacteriophages (phages) were covalently immobilized on polydimethylsiloxane (PDMS) surface containing the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP) via SNAP impregnation method. This dual strategy combines the targeted antibacterial activity of phages against bacterial pathogens with the antibacterial-antithrombotic activity of NO released from the polymeric surface. The PDMS, SNAP-PDMS, phage-immobilized PDMS (PDMS-Phage), and phage-immobilized SNAP-PDMS (SNAP-PDMS-Phage) surfaces were characterized for their surface topology, elemental composition, contact angle, SNAP loading, NO release and phage distribution. SNAP-PDMS and SNAP-PDMS-Phage surfaces showed similar and consistent NO release profiles over 24 h of incubation. Immobilization of whole phages on PDMS and SNAP-PDMS was achieved with densities of 2.4 ± 0.54 and 2.1 ± 0.33 phages μm^-2, respectively. Immobilized phages were found to retain their activity, and SNAP-PDMS-Phage surfaces showed a significant reduction in planktonic (99.99 ± 0.08%) as well as adhered (99.80 ± 0.05%) Escherichia coli as compared to controls in log killing assays. The SNAP-PDMS-Phage surfaces also exhibited significantly reduced platelet adhesion by 64.65 ± 2.95% as compared to control PDMS surfaces. All fabricated surfaces were found to be nonhemolytic and do not exhibit any significant cytotoxic effects toward mammalian fibroblast cells. This study is the first of its kind to demonstrate the combinatorial pertinence of phages and NO to prevent antibiotic-resistant/sensitive bacterial infections and thrombosis associated with indwelling medical devices.

The process of locally increasing the permeability of cell membranes or cell layers is referred to as sonoporation or sonopermeation, respectively, and opens up perspectives for drug delivery in cancer treatment by facilitating enhanced local drug accumulation. These effects are mediated by ultrasound-activated microbubbles in close proximity to cells. Here, the selection of ultrasound settings according to the intended effect on the biological tissue remains a challenge, especially for broadly size-distributed microbubbles, which show a heterogeneous response to ultrasound. For this purpose, we have analyzed the general response of narrower size-distributed poly(n-butyl cyanoacrylate) hard-shelled microbubbles to ultrasound via ultra-high-speed imaging and evaluated their ability to stimulate sonoporation and sonopermeation in vitro compared to lipid soft-shelled microbubbles. Ultra-high-speed imaging of hard-shelled microbubbles revealed either a compression-dominated or compression-only response at peak negative acoustic pressures higher than 165 kPa and an onset of bursting at 500 kPa. The in vitro experiments demonstrated that the hard-shelled microbubbles induced significant sonoporation and sonopermeation effects, also when only compressing at 300 kPa peak neagtive pressure. Compared to soft-shelled microbubbles, the effects were less prominent, which was attributed to differences in their ultrasound responses and size distributions. This in vitro validation of hard-shelled microbubbles qualifies them for future in vivo applications, which would benefit from their narrow size distribution, thereby allowing more control of their therapeutic effect by suitably adjusting the ultrasound parameters.

Surface-enhanced Raman scattering (SERS) is an ultrasensitive optical technique that is critical for protein detection and essential for identifying protein structure and concentrations in various biomedical and diagnostic applications. However, achieving highly sensitive and reproducible SERS signals for label-free proteins remains challenging due to their weak Raman signals and structural complexity. In this study, silver nanomushroom arrays (Ag NMAs) as SERS substrates were readily prepared and surface-engineered using a facile template-assisted micro- and nanofabrication approach. The surface of the substrate exhibits nanoscale roughness, long-range order, and hydrophilicity, enabling rapid and uniform dispersion of protein molecules. These molecules are anchored through Ag-S bonds, resulting in ultrasensitive Raman signals driven by strong electromagnetic enhancement effects. The highly ordered array structure improves signal repeatability, achieving a relative standard deviation of as low as 4.32%. Additionally, utilizing the silicon characteristic peak of the SERS substrate as an internal standard significantly reduces measurement errors, allowing for reliable and precise quantitative detection of protein molecules, with a linear correlation coefficient (R²) exceeding 0.96. Ultrasensitive SERS detection and effective protein discrimination via principal component analysis further validate the Ag NMA substrate's potential for universal trace protein detection. This study presents an advanced SERS platform for the sensitive and rapid detection of trace proteins, showcasing significant potential in pharmaceutical research, metabolic studies, diagnostic medicine, and protein engineering.