The current work focuses on the fabrication of high-molecular-weight stereocomplex poly(lactic acid)/nanohydroxyapatite (sPLA/n-HAP)-based bionanocomposite for three-dimensional (3D)-printed orthopedic implants and high-temperature engineering applications. To achieve the same, n-HAP is grafted with poly(d-lactic acid) (PDLA) via in situ ring-opening polymerization of d-lactide, followed by blending with poly(l-lactic acid) (PLLA), which yields sPLA/n-HAP biocomposite with improved storage modulus even at temperatures higher than 140 °C. X-ray diffraction and calorimetric analysis ensure the presence of 100% stereocomplex crystallites of biocomposite along with significant improvement in the melting temperature (∼227 °C). Noteworthy improvements in the mechanical and gas-barrier properties of the developed biocomposites are achieved due to the uniform dispersion of n-HAP (∼60 nm) confirmed by morphological studies. An unusual improvement in elongation at break (∼130% at 1 wt % HAP loading) makes this composite a toughened material. However, the tensile strength is improved by ∼16%, whereas oxygen permeability and water vapor transmission rate are found to reduce by ∼48 and ∼34%, respectively. Interestingly, the developed material is processed as monofilament, followed to 3D printing to yield a middle phalanx bone as a representative example of orthopedic implants. In vitro studies reveal that cell adhesion and proliferation on the surface of the developed biocomposite support its biocompatible nature. This signifies the possible future aspects of the material in commercial biomedical and high-temperature engineering applications.

The article demonstrates the crystalline silk nano‐discs (CSNs), with well‐controlled morphology, which upon magnetization, yields magnetic crystalline silk nano‐discs, making both prominent alternatives for replacing metal templates such as gold, silver, and so on in therapeutics and implants. The isolated β‐sheet‐rich discotic CSNs have ~50 nm diameter, high crystallinity (> 90%), and are insoluble but provide good dispersibility and stability in aqueous solutions. The melt blending‐cum‐electrospinning of functionalized CSN with poly(lactic acid) results in biocompatible nanofiber‐based scaffolds having in vitro cell cytocompatibility with improved cell adhesion and proliferation. The assessment of release behavior of curcumin, a naturally occurring anticancer drug, shows sustained release over 25 days exhibiting effective cytotoxicity against human cervical cancer cells. Further, combined effect of curcumin and hyperthermia reduced the cell growth by ~63%. Alignment of CSN‐derived magnetic nanoparticles due to effective fiber drawing process during electrospinning could improve cytocompatibility against BHK‐21 cells, and therefore efficacy for cancer therapy.

The current research concentrates on the synthesis of linear block copolymers with their backbone consisting of hard and soft segments, that is, poly­(L-lactic acid) (PLLA)/ poly­(D-lactic acid) (PDLA) and poly­(ε-caprolactone) (PCL), with the detailed investigation of the effect of block length on the thermal, mechanical, and crystallization behavior followed by their processing and biocompatibility evaluation. In the current work, sequential ring opening polymerization has been employed wherein PCL is used as a macroinitiator for the synthesis of diblock (PCL-PDLA and PCL-PLLA) and stereotriblock copolymers (PCL-PLLA-PDLA) of targeted molecular weight, which is confirmed by 1H NMR spectroscopy. The block length of PCL, in the case of diblock copolymer, is fixed; however, that of PLLA or PDLA is varied, and the enantiomeric blends thereof are made to achieve the merits of stereocomplexation. The length of the individual blocks is the same in the case of stereotriblock copolymer. The presence of two crystalline domains is manifested from differential scanning calorimetry and thermogravimertric analysis. An interesting improvement in the mechanical properties is observed upon increasing the block length of PDLA/PLLA in the block copolymer system which may be ascribed to the confined crystalliztion of PCL in the microdomain structure. Additionally, the synthesized materials are found to support the adhesion of MG-63 (human bone osteoscarcoma) cells as determined from in vitro studies indicating their potential in bone repair and regeneration. Further, the block copolymers possessing superior mechanical properties are thermally processed by injection molding to fabricate representative orthopedic fixation devices such as cancellous and cortical bone screws. Eventually, the thermo-mechanical stability of the cancellous bone screw made from the synthesized block copolymer is presented as compared to that made from the commercial PLA at the sterilization temperature of the biomedical devices.

The current research unfolds the effect of block lengths, microdomain morphology and stereocomplexation on the mechanical properties of PLA-b-PCL-b-PLA triblock copolymers where PCL is involved to improve the poor extensibility of PLA.

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Chitosan is a natural polymer obtained from exoskeletons of crustaceans and polyvinyl alcohol (PVA) is a synthetic polymer which has excellent film forming ability along with non-toxic nature. The current work focuses on synthesizing a smart polymer by copolymerization of natural and synthetic polymers and exploring its applications in drug delivery. The copolymers were blended in different ratios and were synthesized using ammonium ceric nitrate as initiator and glutaraldehyde as a crosslinking agent which were converted to films by casting method. Amoxicillin, as a model drug was incorporated to the copolymerized films to study the in-vitro drug release. The films obtained were evaluated by varying the pH to study the pH responsive nature of films. Drug release studies were performed to obtain the release profile of drug; water uptake capacity of the copolymerized film were measured to determine the swelling behaviour of the films. The films were further characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) to identify the structural and morphological changes along with thermal transitions. The results indicate that the synthesized copolymers are pH responsive in nature having great potential for application in controlled and targeted drug delivery.

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