Biomaterials and Contraception: Promises and Pitfalls.

The present state of reproductive and sexual health around the world reveals disparities in contraceptive use and effectiveness. Unintended pregnancy and sexually transmitted infection transmission rates remain high even with current prevention methods. The 20th century saw a contraceptive revolution with biomedical innovation driving the success of new contraceptive technologies with central design concepts and materials. Current modalities can be broadly categorized according to their mode of function: reversible methods such as physical/chemical barriers or hormonal delivery devices via systemic (transdermal and subcutaneous) or localized (intrauterine and intravaginal) administration, and nonreversible sterilization procedures such as tubal ligation and vasectomy. Contraceptive biomaterials are at present dominated by well-characterized elastomers such as polydimethylsiloxane and ethylene vinyl acetate due to their favorable material properties and versatility. Contraceptives alter the normal function of cellular components in the reproductive systems to impair fertility. The purpose of this review is to highlight the bioengineering design of existing methods, explore novel adaptations, and address notable shortcomings in current contraceptive technologies.

Enzymatically crosslinked gelatin-laminin hydrogels for applications in neuromuscular tissue engineering.

We report a water-soluble and non-toxic method to incorporate additional extracellular matrix proteins into gelatin hydrogels, while obviating the use of chemical crosslinkers such as glutaraldehyde. Gelatin hydrogels were fabricated using a range of gelatin concentrations (4%-10%) that corresponded to elastic moduli of approximately 1 kPa-25 kPa, respectively, a substrate stiffness relevant for multiple cell types. Microbial transglutaminase was then used to enzymatically crosslink a layer of laminin on top of gelatin hydrogels, resulting in 2-component gelatin-laminin hydrogels. Human induced pluripotent stem cell derived spinal spheroids readily adhered and rapidly extended axons on GEL-LN hydrogels. Axons displayed a more mature morphology and superior electrophysiological properties on GEL-LN hydrogels compared to the controls. Schwann cells on GEL-LN hydrogels adhered and proliferated normally, displayed a healthy morphology, and maintained the expression of Schwann cell specific markers. Lastly, skeletal muscle cells on GEL-LN hydrogels achieved long-term culture for up to 28 days without delamination, while expressing higher levels of terminal genes including myosin heavy chain, MyoD, MuSK, and M-cadherin suggesting enhanced maturation potential and myotube formation compared to the controls. Future studies will employ the superior culture outcomes of this hybrid substrate for engineering functional neuromuscular junctions and related organ on a chip applications.

Engineered Microenvironments for Maturation of Stem Cell Derived Cardiac Myocytes.

Through the use of stem cell-derived cardiac myocytes, tissue-engineered human myocardial constructs are poised for modeling normal and diseased physiology of the heart, as well as discovery of novel drugs and therapeutic targets in a human relevant manner. This review highlights the recent bioengineering efforts to recapitulate microenvironmental cues to further the maturation state of newly differentiated cardiac myocytes. These techniques include long-term culture, co-culture, exposure to mechanical stimuli, 3D culture, cell-matrix interactions, and electrical stimulation. Each of these methods has produced various degrees of maturation; however, a standardized measure for cardiomyocyte maturation is not yet widely accepted by the scientific community.