Health Care Innovation for Low-Resource Settings: The Value of Local Immersion and Partnership

Health Care Innovation is the creation, development, and translation of new and better solutions to health care challenges. At its core, this endeavor does not require extending the frontiers of science or the creation of new fundamental technologies. Rather, it is primarily focused on the use of existing science and established technologies in the design of new solutions to problems in health care. Successfully innovating for low- and middle-income countries (LMICs) requires a needs and stakeholder-driven approach to enable development and adoption of available, accessible, and acceptable solutions tailored to the specific need and context of care.

A new era in posterior segment ocular drug delivery: Translation of systemic, cell-targeted, dendrimer-based therapies

Vision impairment and loss due to posterior segment ocular disorders, including age-related macular degeneration and diabetic retinopathy, are a rapidly growing cause of disability globally. Current treatments consist primarily of intravitreal injections aimed at preventing disease progression and characterized by high cost and repeated clinic visits. Nanotechnology provides a promising platform for drug delivery to the eye, with potential to overcome anatomical and physiological barriers to provide safe, effective, and sustained treatment modalities. However, there are few nanomedicines approved for posterior segment disorders, and fewer that target specific cells or that are compatible with systemic administration. Targeting cell types that mediate these disorders via systemic administration may unlock transformative opportunities for nanomedicine and significantly improve patient access, acceptability, and outcomes. We highlight the development of hydroxyl polyamidoamine dendrimer-based therapeutics that demonstrate ligand-free cell targeting via systemic administration and are under clinical investigation for treatment of wet age-related macular degeneration.

Nanofiber-coated, tacrolimus-eluting sutures inhibit post-operative neointimal hyperplasia in rats

Post-operative complications of vascular anastomosis procedures remain a significant clinical challenge and health burden globally. Each year, millions of anastomosis procedures connect arteries and/or veins in vascular bypass, vascular access, organ transplant, and reconstructive surgeries, generally via suturing. Dysfunction of these anastomoses, primarily due to neointimal hyperplasia and the resulting narrowing of the vessel lumen, results in failure rates of up to 50% and billions of dollars in costs to the healthcare system. Non-absorbable sutures are the gold standard for vessel anastomosis; however, damage from the surgical procedure and closure itself causes an inflammatory cascade that leads to neointimal hyperplasia at the anastomosis site. Here, we demonstrate the development of a novel, scalable manufacturing system for fabrication of high strength sutures with nanofiber-based coatings composed of generally regarded as safe (GRAS) polymers and either sirolimus, tacrolimus, everolimus, or pimecrolimus. These sutures provided sufficient tensile strength for maintenance of the vascular anastomosis and sustained drug delivery at the site of the anastomosis. Tacrolimus-eluting sutures provided a significant reduction in neointimal hyperplasia in rats over a period of 14 days with similar vessel endothelialization in comparison to conventional nylon sutures. In contrast, systemically delivered tacrolimus caused significant weight loss and mortality due to toxicity. Thus, drug-eluting sutures provide a promising platform to improve the outcomes of vascular interventions without modifying the clinical workflow and without the risks associated with systemic drug delivery.

DescePrep Significantly Increases Descemet Membrane Endothelial Keratoplasty Processing Efficiency and Success Rate in Diabetic Human Donor Corneas in Comparison With Manual Dissection

PURPOSE

The purpose of this study was to compare the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft processing device, DescePrep, with a manual dissection technique through the measurement of tissue yield, processing time, and graft viability in nondiabetic and diabetic donor corneas.

METHODS

Nondiabetic (n = 20) and diabetic (n = 20) donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Nondiabetic (n = 20) and diabetic (n = 24) donor corneas were also processed through manual dissection. Corneas were stained, processed, and then evaluated for processing success rate and time. Randomly selected corneas (n = 5, each) were evaluated for cell viability using live/dead staining.

RESULTS

One hundred percent of nondiabetic and 95% of diabetic corneas were processed successfully with DescePrep in an average of 3.37 minutes. Ninety percent of nondiabetic and 50% of diabetic corneas were processed successfully with manual dissection in an average of 9.87 minutes. DescePrep had a significantly lower processing time ( P < 0.0001) and significantly higher success rate in comparison with manual dissection. DescePrep grafts had an average cell viability of 91.1% ± 3.3% in nondiabetic and 91.5% ± 2.4% in diabetic corneas. Grafts prepared with manual dissection had an average cell viability of 89.5% ± 5.8% in nondiabetic and 88.1% ± 4.3% in diabetic corneas.

CONCLUSIONS

DescePrep provides a more effective and efficient method of cornea preparation in comparison with the current standard, particularly in diabetic corneas, while providing comparable cell viability. Thus, DescePrep offers standardized DMEK processing that produces high-quality grafts at high yields, with the potential to expand access and improve the quality of DMEK graft preparation in a larger pool of donors.

Digital lock-in amplifier for space rubidium atomic clock

In many low-noise applications, extracting information from the extremely noisy signal is required. This task can be accomplished by a lock-in amplifier if the frequency of the signal is known before detection. Error signal output from the physics package of the rubidium atomic clock (RbAC) is one of those noisy signals. A lock-in amplifier extracts the desired information from such a signal as the frequency of the error signal is known beforehand. The Space Applications Centre of the Indian Space Research Organisation is developing the Indian Rubidium Atomic Frequency Standard (IRAFS) for Navigation with Indian Constellation. We have developed a digital lock-in amplifier with a very high-resolution frequency control voltage for IRAFS. This paper demonstrates the digital lock-in amplifier with a novel method of combining two 12-bit digital-to-analog converters (DACs) to get higher resolution 20-bit output for precise frequency control and tuning. This design technique allows a digital lock-in amplifier to be used for high-performance RbAC for space applications as precision DACs with higher resolution are not available in space-qualified versions.

Evaluation of Efficacy, Efficiency, and Cell Viability of a Novel Descemet Membrane Endothelial Keratoplasty Graft Preparation Device, DescePrep, in Nondiabetic and Diabetic Human Donor Corneas

PURPOSE

The purpose of this study was to evaluate the safety, efficacy, and efficiency of a Descemet membrane endothelial keratoplasty (DMEK) graft preparation device, DescePrep, through measurement of graft viability, yield, and preparation time in both healthy and diabetic (high-risk) donor eyes.

METHODS

Twenty nondiabetic and 10 diabetic donor corneas were processed using DescePrep, which standardizes the liquid bubble technique. Corneas were stained with trypan blue and then processed. Cell counts through specular microscopy, optical coherence tomography imaging, and slit-lamp analysis were used for the evaluation of graft separation and viability in 5 nondiabetic corneas. The remaining 25 corneas (15 nondiabetic and 10 diabetic) were evaluated for preparation success rate and processing time. Ten corneas (5 nondiabetic and 5 diabetic) were randomly selected for further evaluation of global cell loss through staining.

RESULTS

Ninety-seven percent of corneas (29 of 30) were prepared successfully with DescePrep. The average preparation time was 2.83 ± 1.8 minutes. There was no significant difference in the time of preparation between the nondiabetic and diabetic groups (P = 0.077). The overall average cell death after processing was 7.9% ± 3.7% for all corneas. There was no significant difference in cell viability between diabetic and nondiabetic tissues after DescePrep processing (P = 0.769).

CONCLUSIONS

DescePrep is a new DMEK preparation technique that can process both nondiabetic and diabetic donor corneas at high yields in minutes. High-yield preparation of diabetic corneas may offer eye banks access to a larger donor , which is important because the demand for DMEK grafts continues to rise worldwide.

Engineering biomaterials to prevent post-operative infection and fibrosis

Implantable biomaterials are essential surgical devices, extending and improving the quality of life of millions of people globally. Advances in materials science, manufacturing, and in our understanding of the biological response to medical device implantation over several decades have resulted in improved safety and functionality of biomaterials. However, post-operative infection and immune responses remain significant challenges that interfere with biomaterial functionality and host healing processes. The objectives of this review is to provide an overview of the biology of post-operative infection and the physiological response to implanted biomaterials and to discuss emerging strategies utilizing local drug delivery and surface modification to improve the long-term safety and efficacy of biomaterials.

Addressing the MSICS learning curve: identification of instrument-holding techniques used by experienced surgeons

AIM

To identify instrument holding archetypes used by experienced surgeons in order to develop a universal language and set of validated techniques that can be utilized in manual small incision cataract surgery (MSICS) curricula.

METHODS

Experienced cataract surgeons performed five MSICS steps (scleral incision, scleral tunnel, side port, corneal tunnel, and capsulorhexis) in a wet lab to record surgeon hand positions. Images and videos were taken during each step to identify validated hand position archetypes.

RESULTS

For each MSICS step, one or two major archetypes and key modifying variables were observed, including tripod for scleral incision, tripod-thumb bottom for scleral tunnel, underhand-index to thumb grip for side port, index-contact tripod for corneal entry, and tripod-forceps for capsulorhexis. Key differences were noted in thumb placement and number of fingers supporting the instrument, and modifying variables included index finger curvature and amount of flexion.

CONCLUSION

Identification of optimal hand positions and development of a formal nomenclature has the potential to help trainees adopt hand positions in an informed manner, influence instrument design, and improve surgical outcomes.

Ultra-thin, high strength, antibiotic-eluting sutures for prevention of ophthalmic infection

Sutures are applied almost universally at the site of trauma or surgery, making them an ideal platform to modulate the local, postoperative biological response, and improve surgical outcomes. To date, the only globally marketed drug-eluting sutures are coated with triclosan for antibacterial application in general surgery. Loading drug directly into the suture rather than coating the surface offers the potential to provide drug delivery functionality to microsurgical sutures and achieve sustained drug delivery without increasing suture thickness. However, conventional methods for drug incorporation directly into the suture adversely affect breaking strength. Thus, there are no market offerings for drug-eluting sutures, drug-coated, or otherwise, in ophthalmology, where very thin sutures are required. Sutures themselves help facilitate bacterial infection, and antibiotic eye drops are commonly prescribed to prevent infection after ocular surgeries. An antibiotic-eluting suture may prevent bacterial colonization of sutures and preclude patient compliance issues with eye drops. We report twisting of hundreds of individual drug-loaded, electrospun nanofibers into a single, ultra-thin, multifilament suture capable of meeting both size and strength requirements for microsurgical ocular procedures. Nanofiber-based polycaprolactone sutures demonstrated no loss in strength with loading of 8% levofloxacin, unlike monofilament sutures which lost more than 50% strength. Moreover, nanofiber-based sutures retained strength with loading of a broad range of drugs, provided antibiotic delivery for 30 days in rat eyes, and prevented ocular infection in a rat model of bacterial keratitis.

Nano-structured glaucoma drainage implant safely and significantly reduces intraocular pressure in rabbits via post-operative outflow modulation

Glaucoma is a leading cause of irreversible vision loss predicted to affect more than 100 million people by 2040. Intraocular pressure (IOP) reduction prevents development of glaucoma and vision loss from glaucoma. Glaucoma surgeries reduce IOP by facilitating aqueous humor outflow through a vent fashioned from the wall of the eye (trabeculectomy) or a glaucoma drainage implant (GDI), but surgeries lose efficacy overtime, and the five-year failure rates for trabeculectomy and tube shunts are 25-45%. The majority of surgical failures occur due to fibrosis around the vent. Alternatively, surgical procedures can shunt aqueous humor too well, leading to hypotony. Electrospinning is an appealing manufacturing platform for GDIs, as it allows for incorporation of biocompatible polymers into nano- or micro-fibers that can be configured into devices of myriad combinations of dimensions and conformations. Here, small-lumen, nano-structured glaucoma shunts were manufactured with or without a degradable inner core designed to modulate aqueous humor outflow to provide immediate IOP reduction, prevent post-operative hypotony, and potentially offer significant, long-term IOP reduction. Nano-structured shunts were durable, leak-proof, and demonstrated biocompatibility and patency in rabbit eyes. Importantly, both designs prevented hypotony and significantly reduced IOP for 27 days in normotensive rabbits, demonstrating potential for clinical utility.

Development of Absorbable, Antibiotic-Eluting Sutures for Ophthalmic Surgery

Purpose

To develop and evaluate an antibiotic-eluting suture for ophthalmic surgery.

Methods

Wet electrospinning was used to manufacture sutures composed of poly(L-lactide), polyethylene glycol (PEG), and levofloxacin. Size, morphology, and mechanical strength were evaluated via scanning electron microscopy and tensile strength, respectively. In vitro drug release was quantified using high performance liquid chromatography. In vitro suture activity against Staphylococcus epidermidis was investigated through bacterial inhibition studies. Biocompatibility was determined via histological analysis of tissue sections surrounding sutures implanted into Sprague-Dawley rat corneas.

Results

Sutures manufactured via wet electrospinning were 45.1 ± 7.7 μm in diameter and 0.099 ± 0.007 newtons (N) in breaking strength. The antibiotic release profile demonstrated a burst followed by sustained release for greater than 60 days. Increasing PEG in the polymer formulation, from 1% to 4% by weight, improved drug release without negatively affecting tensile strength. Sutures maintained a bacterial zone of inhibition for at least 1 week in vitro and elicited an in vivo tissue reaction comparable to a nylon suture.

Conclusions

There is a need for local, postoperative delivery of antibiotics following ophthalmic procedures. Wet electrospinning provides a suitable platform for the development of sutures that meet size requirements for ophthalmic surgery and are capable of sustained drug release; however, tensile strength must be improved prior to clinical use.

Translational Relevance

No antibiotic-eluting suture exists for ophthalmic surgery. A biocompatible, high strength suture capable of sustained antibiotic release could prevent ocular infection and preclude compliance issues with topical eye drops.

Cell attachment to hydrogel-electrospun fiber mat composite materials

Hydrogels, electrospun fiber mats (EFMs), and their composites have been extensively studied for tissue engineering because of their physical and chemical similarity to native biological systems. However, while chemically similar, hydrogels and electrospun fiber mats display very different topographical features. Here, we examine the influence of surface topography and composition of hydrogels, EFMs, and hydrogel-EFM composites on cell behavior. Materials studied were composed of synthetic poly(ethylene glycol) (PEG) and poly(ethylene glycol)-poly(ε-caprolactone) (PEGPCL) hydrogels and electrospun poly(caprolactone) (PCL) and core/shell PCL/PEGPCL constituent materials. The number of adherent cells and cell circularity were most strongly influenced by the fibrous nature of materials (e.g., topography), whereas cell spreading was more strongly influenced by material composition (e.g., chemistry). These results suggest that cell attachment and proliferation to hydrogel-EFM composites can be tuned by varying these properties to provide important insights for the future design of such composite materials.

Hydrogel-electrospun fiber mat composite coatings for neural prostheses

Achieving stable, long-term performance of implanted neural prosthetic devices has been challenging because of implantation related neuron loss and a foreign body response that results in encapsulating glial scar formation. To improve neuron–prosthesis integration and form chronic, stable interfaces, we investigated the potential of neurotrophin-eluting hydrogel–electrospun fiber mat (EFM) composite coatings. In particular, poly(ethylene glycol)-poly(ε-caprolactone) (PEGPCL) hydrogel–poly(ε-caprolactone) EFM composites were applied as coatings for multielectrode arrays. Coatings were stable and persisted on electrode surfaces for over 1 month under an agarose gel tissue phantom and over 9 months in a PBS immersion bath. To demonstrate drug release, a neurotrophin, nerve growth factor (NGF), was loaded in the PEGPCL hydrogel layer, and coating cytotoxicity and sustained NGF release were evaluated using a PC12 cell culture model. Quantitative MTT assays showed that these coatings had no significant toxicity toward PC12 cells, and neurite extension at day 7 and 14 confirmed sustained release of NGF at biologically significant concentrations for at least 2 weeks. Our results demonstrate that hydrogel–EFM composite materials can be applied to neural prostheses to improve neuron–electrode proximity and enhance long-term device performance and function.

Foetal growth parameters--clinical versus ultrasonographic

The study was conducted in 2831 pregnant women with no diagnosed complication at the time of registration to obtain normal foetal growth pattern for clinical and ultrasonographic parameters. Normal values for maternal weight, fundal height and abdominal girth for clinical and biparietal diameter, abdominal circumferences and femoral length for ultrasonographic parameters are presented. Clinical and ultrasonographic parameters were compared for their efficacy in prediction of low birth weight. Neither clinical nor ultrasonographic parameters were found to be satisfactory in identifying the foetus at risk of low birth weight. It has been found that clinical parameters for routine monitoring are as effective as ultrasonographic parameters and have the added advantage of being easily replicable at the peripheral level of health care.

Food and energy choices for India: a programming model with partial endogenous energy requirements

This paper presents a mathematical model for all matter-energy processing subsystems at the level of the society, specifically India. It explores India's choices in the food and energy sectors over the coming decades. Alternative land intensive, irrigation energy intensive, and fertilizer intensive techniques of food production are identified using a nonlinear programming model. The land saved is devoted to growing firewood. The optimum combination of railway (steam, diesel, and electric traction) and road (automobiles, diesel trucks, and diesel and gasoline buses) transport is determined. For the oil sector, two alternative sources of supply of crude oil and petroleum products are included, namely, domestic production and imports. The optimum choice is determined through a linear programming model. While the model is basically a static one, designed to determine the optimal choice for the target year of 2000-2001, certain intertemporal detail is incorporated for electricity generation. The model minimizes the costs of meeting the needs for food, transport in terms of passenger kilometers and goods per ton per kilometer, energy needs for domestic cooking and lighting, and the energy needs of the rest of the economy.