Evaluation of a novel flow-controlled syringe infusion pump for precise and continuous drug delivery at low flow rates: a laboratory study

Syringe infusion pumps are used for the administration of short-acting drugs in anaesthesia and critical care medicine, but are prone to flow irregularities at low flow rates. A flow-controlled syringe infusion pump using an integrated flow sensor for feedback control represents a new approach to overcoming these limitations. This study compares the performance of a prototype flow-controlled syringe pump both at start-up, and during vertical displacement manoeuvres, with that of a standard infusion syringe pump. The novel pump almost completely eliminated delays at start-up and flow irregularities during hydrostatic pressure changes. Related fluctuations in plasma drug concentration were minimised and the known disadvantages of standard syringe infusion pumps currently used in clinical practice were reduced. Besides providing fast start-up to steady-state flow and precise continuous drug delivery at low flow rates during hydrostatic pressure changes, the new pump offers the potential for the development of target-controlled infusion algorithms for short-acting cardiovascular and other drugs.

Fabrication of Bioengineered Skin by Injection Molding: A Feasibility Study on Automation

The use of bioengineered skin has facilitated fundamental and applied research because it enables the investigation of complex interactions between various cell types as well as the extracellular matrix. The predominantly manual fabrication of these living tissues means, however, that their quality, standardization, and production volume are extremely dependent on the technician's experience. Simple laboratory automation could facilitate the use of living tissues by a greater number of research groups. We developed and present here an injection molding technique for the fabrication of bilayered skin equivalents. The tissue was formed automatically by two separate injections into a customized mold to produce the dermal and epidermal skin layers. We demonstrated the biocompatibility of this fabrication process and confirmed the resulting bilayered morphology of the bioengineered skin using histology and immunohistochemistry. Our findings highlight the possibility of fabricating multilayered living tissue by injection molding, suggesting that further investigation into this automation method could result in the rapid and low-cost fabrication of standardized bioengineered skin.

A simplified fabrication technique for cellularized high-collagen dermal equivalents

Human autologous bioengineered skin has been successfully developed and used to treat skin injuries in a growing number of cases. In current clinical studies, the biomaterial used is fabricated via plastic compression of collagen hydrogel to increase the density and stability of the tissue. To further facilitate clinical adoption of bioengineered skin, the fabrication technique needs to be improved in terms of standardization and automation. Here, we present a one-step mixing technique using highly concentrated collagen and human fibroblasts to simplify fabrication of stable dermal equivalents. As controls, we prepared cellularized dermal equivalents with three varying collagen compositions. We found that the dermal equivalents produced using the simplified mixing technique were stable and pliable, showed viable fibroblast distribution throughout the tissue, and were comparable to highly concentrated manually produced collagen gels. Because no subsequent plastic compression of collagen is required in the simplified mixing technique, the fabrication steps and production time for dermal equivalents are consistently reduced. The present study provides a basis for further investigations to optimize the technique, which has significant promise in enabling efficient clinical production of bioengineered skin in the future.