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1.
J Funct Biomater ; 15(2)2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38391887

RESUMO

Besides the need for biomaterial surface modification to improve cellular attachment, laser-structuring is favorable for designing a new surface topography for external bone fixator pins or implants. The principle of this study was to observe how bioinspired (deer antler) laser-induced nano-microstructures influenced the adhesion and growth of skin cells. The goal was to create pins that allow the skin to attach to the biomaterial surface in a bacteria-proof manner. Therefore, typical fixator metals, steel, and titanium alloy were structured using ultrashort laser pulses, which resulted in periodical nano- and microstructures. Surface characteristics were investigated using a laser scanning microscope and static water contact angle measurements. In vitro studies with human HaCaT keratinocytes focused on cell adhesion, morphology, actin formation, and growth within 7 days. The study showed that surface functionalization influenced cell attachment, spreading, and proliferation. Micro-dimple clusters on polished bulk metals (DC20) will not hinder viability. Still, they will not promote the initial adhesion and spreading of HaCaTs. In contrast, additional nanostructuring with laser-induced periodic surface structures (LIPSS) promotes cell behavior. DC20 + LIPSS induced enhanced cell attachment with well-spread cell morphology. Thus, the bioinspired structures exhibited a benefit in initial cell adhesion. Laser surface functionalization opens up new possibilities for structuring, and is relevant to developing bioactive implants in regenerative medicine.

2.
Biomed Tech (Berl) ; 68(1): 67-77, 2023 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-36165737

RESUMO

One application in the medical treatment at very small flow rates is the usage of an Insulin pump that delivers doses of insulin at constant cycle times for a specific basal rate as quasi-continuous insulin delivery, which is an important cornerstone in diabetes management. The calibration of these basal rates are performed by either gravimetric or optical methods, which have been developed within the European Metrology Program for Innovation and Research (EMPIR) Joint Research Project (JRP) 18HLT08 Metrology for drug delivery II (MeDDII). These measurement techniques are described in this paper, and an improved approach of the analytical procedure given in the standard IEC 60601-2-24:2012 for determining the discrete doses and the corresponding basal rates is discussed in detail. These improvements allow detailed follow up of dose cycle time and delivered doses as a function of time to identify some artefacts of the measurement method or malfunctioning of the insulin pump. Moreover, the calibration results of different basal rates and bolus deliveries for the gravimetric and the optical methods are also presented. Some analysis issues that should be addressed to prevent misinterpreting of the calibration results are discussed. One of the main issues is the average over a period of time which is an integer multiple of the cycle time to determine the basal rate with the analytical methods described in this paper.


Assuntos
Hipoglicemiantes , Insulina , Hipoglicemiantes/uso terapêutico , Calibragem , Insulina/uso terapêutico , Sistemas de Infusão de Insulina , Glicemia
3.
Med Eng Phys ; 48: 39-48, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28619594

RESUMO

The presented optical flow metering methods are appropriate to characterise the dynamic properties of microfluidic systems. The dynamic behaviour of clinical or medical devices, micro pumps and flow sensors based on thermal methods were investigated. The Camera-System covers a flow range from 50nl/min to 500µl/min. The uncertainty is less than 4%, sample rates up to 5kS/s. The Displacement-Sensor-System covers a flow range between 100µl/min and 50ml/min. The uncertainty is less than 3% at sample rates up to 49kS/s. It was shown that measuring pulsating flow rates with thermal flow sensors is possible, but the signal is low pass filtered. The low pass behaviour is determined by the thermal properties, thermal resistance and heat capacity, of the flow channel. But the mean flow rate was always measured properly. The fluidic properties of two different types of micro pumps were examined and characterised exemplary.


Assuntos
Dispositivos Lab-On-A-Chip , Fenômenos Ópticos , Desenho de Equipamento , Fatores de Tempo
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