Recent Advancement of Microneedle Technique in Diagnosis and Therapy of Diseases

The therapeutic efficacy and safety of active ingredients are limited in several dosage forms, especially for those where the skin is the prime application area. Injectable has the potential of high efficacy and bioavailability but needle phobia, painful delivery, inflammatory response, and non-compliance make them less usable. Microneedle (MN) delivery overcomes almost all the limitations by offering painless self-administration, is highly effective, economical, avoids waste generation, and has high patient compliance. The MN technique is unique and novel for delivering all therapeutic moieties, vaccines, and micro and macromolecular drugs. The MN delivery is based on the mechanism of poke and patch, coat and patch, poke and release, poke and flow. The several types of MN utilized are solid, coated, hollow, dissolving, and hydrogel-forming microneedles. The materials fabricating MNs are mainly non-degradable (metals, PVP, PVA, etc.) and degradable (natural, PLGA, PAMA, etc.). MN delivery finds significant application in diagnosing several diseases by collecting blood samples and biological fluids with minimal pain. Moreover, the tremendous significance of the MN technique is observed in vaccines, hormones, proteins, peptides, psoriasis, ocular diseases, rheumatoid arthritis, malaria, gene delivery, and cosmetics. The delivery of several kinds of injections in cancer therapy is also harrowing. MN delivery worked excellently by delivering immunotherapeutic, immune checkpoint suppressors, photothermal therapy, and photodynamic therapy and thus valuable for targeting cancer with high success and minimal toxicity.