Embedded nanomicro syringe on chip for molecular therapy

Skin drug permeability and safety through a vibrating solid micro-needle system

Micro-needles and sonophoresis are two physical methods for enhancing skin permeation for transdermal drug delivery. A solid micro-needle system with vertical vibration was integrated and its effects on transdermal drug delivery were studied. Evan's blue (EB) staining and histological evaluation were performed to reveal the skin morphology and micro-conduits created by vibrating micro-needles. Trans-epidermal water loss (TEWL) and infection studies on rat's skin after vibrating micro-needle treatment were performed to evaluate the safety of the treatment. In vivo insulin delivery and tetramethylpyrazine hydrochloride (TMPH) permeation were carried out to assess the effectiveness of the transdermal drug delivery using the vibrating micro-needle system. The structural integrity of vibrated micro-needles was studied through SEM photos. EB staining observation showed that EB has diffused significantly on the skin surface treated with vibrating micro-needles. The micro-conduits were seen by histological visualization. TEWL values increased significantly after treatment as vibration frequency increased. The infection evaluation showed a slight increase of white blood cell number resulted from vibrating micro-needle treatment. The in vivo insulin absorption experiment demonstrated an enhanced transdermal delivery of insulin through vibrating micro-needles treatment, and the effectiveness of blood glucose level increased with increasing vibration frequency. The TMPH permeation study showed an obvious enhanced skin permeability due to vibrating micro-needle pretreatment. The degree of enhancement also increased with vibration frequency. No broken tip of vibrated micro-needle was found after application. The vibrating solid micro-needle was effective and safe for the transdermal administration of hydrophilic drugs. The effectiveness increases with increasing vibration frequency.

Modeling of Drug Delivery by A Pump Driven Micro-Needle Array System

BACKGROUND

Micro-needles were proposed as one of the alternatives to deliver drugs painlessly passing through stratum corneum in recent years. In this work, a mathematical model is presented to characterize the in fusion flow of a hollow micro-needle array driven by a micro-pump.

METHODS

By assuming the injection of each micro-needle undergoes a spherical expansion and diffusion, the model is able to calculate the time-varying expansion radius, and the diffusion boundary, provided that the material properties and the micro-needle system parameters are known.

RESULTS AND CONCLUSION

The calculation results show that the expansion caused by the infusion of micro-needles stops and the flow rate drops to zero in a short time. However, the diffusion boundary is much bigger than the expansion and the infusion continues if the surrounding material is absorptive. The experimental results of jet infusion through a single needle in silicon rubber and polyacrylamide gel agree with the calculation results qualitatively.

Increment of Access Points in Integrated System of Wavelength Division Multiplexed Passive Optical Network Radio over Fiber

This paper describes a novel technique to increase the numbers of access points (APs) in a wavelength division multiplexed-passive optical network (WDM-PON) integrated in a 100 GHz radio-over-fiber (RoF). Eight multi-carriers separated by 25 GHz intervals were generated in the range of 193.025 to 193.200 THz using a microring resonator (MRR) system incorporating an add-drop filter system. All optically generated multi-carriers were utilized in an integrated system of WDM-PON-RoF for transmission of four 43.6 Gb/sec orthogonal frequency division multiplexing (OFDM) signals. Results showed that an acceptable BER variation for different path lengths up to 25 km was achievable for all four access points and thus the transmission of four OFDM channels is feasible for a 25 km standard single mode fiber (SSMF) path length.