Biological performance

The in vitro biocompatibility of CPs has been generally investigated by cell viability, proliferation and cytotoxicity assays of various cell types, including rat pheochromocy-toma cells (PC 12), rat Schwann cells, cardiac myoblasts, astrocytes, and various neural tissue explants [ 13,27,43,47]. Studies on a wide variety of CPs have indicated good in vitro cell responses, with minimal cytotoxicity and, in several cases, preferential adherence of cells to the CP surface, compared to conventional implant materials. However, the majority in vitro studies examine the passive or nonelectrochemically activated state of CPs. Due to the application-specific nature of biocompatibility, passive CP assessment, although a useful preliminary study, is an imperfect characterization of CP biological performance for most implant applications. 

Electrical stimulation has been shown to increase the growth of neurites from neural tissue both on conventional culture substrates and in the presence of CPs [141]. Electrically stimulated CPs have been assessed in vitro, with both clonal cell lines and explant tissue demonstrating increased survival and growth on activated CPs when 

In vivo characterization is more suited to the assessment of CP biological performance, with studies tailored for the intended implant application. In vivo CP studies have been largely limited to electrode recording applications, where CPs have been shown to temporarily improve signal quality [52]. This is due primarily to nemal interactions, discussed further in Section 18.6. Future biological characterization of CPs must focus on in vivo, long-term studies in anatomically appropriate sites with on-going assessment of electrical performance. 

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While the mechanical performance of artificial materials in the human body can be predicted with some rehabihty, forecasting their biological performance is difficnlt. The problem of interactions at surfaces has already been mentioned. Research frontiers also include developing ways to simulate in vivo processes in vitro and extending the power and apphcability of such simulations to allow for better prediction of the performance of biomedical materials and devices in the patient. Fundamental information on the correlation between the in vivo and in vitro responses is limited. Chemical engineers might also make contribntions to the problem of noninvasive monitoring of implanted materials. 

Thomas V, Kumari TV, and Jayabalan M. In vitro studies on the effect of physical cross-linking on the biological performance of aliphatic polyfurethane urea) for blood contact applications. Biomacromolecules, 2001, 2, 588-596. 

Natural pyrethrins, insecticidal ingredients occurring in the flowers of Tanacetum cinerariaefolium (also known as Chrysanthemum cinerariaefolium or Pyrethrum cinerariaefolium), have been modified for higher stability in the environment as well as better biological performance for more than 40 years, and consequently more than 30 synthetic pyrethroids have been marketed and used worldwide for controlling indoor and agricultural pest insects [1,2]. 

Examples of naturally occurring molecular machines and motors are already known. Proteins are the workhorses of cellular biology, performing functions such as transportation, communication, and structural maintenance. Some of these proteins have moving parts and act exactly like small machines. 

Biotechnological transformations include a broad range of processes, ordered according to the number of biologically performed process steps and the complexity of the substrates (Figure 1.2) ... 

While it is easy to focus attention to current plant proteins, the low-abundance species that are probably very active in terms of biological performance are at the same time very numerous and present at trace levels precluding a direct detection possibility with current instruments and methods. It is clear that even more than in animal proteomics, the decrease of the concentration of current proteins and the concomitant enhancement of rare species is mandatory to get a complete picture of the situation. 

Kioukia N, Nienow AW, Emery AN, Al-Rubeai M (1992), The impact of fluid dynamics on the biological performance of free suspension animal cell culture further studies, Trans. I. Chem. Eng. 70 143-148. 

Biopharmaceutics is the study of the interrelationship of the physicochemical properties of the drug [active pharmaceutical ingredient, (API)] and the drug product (dosage form in which the drug is fabricated) based on the biological performance of the drug (Table 1). 

Bio availability is often used as a measure of the biological performance of the drug and is defined as a measure of the rate and extent (amount) to which the active ingredient or active moiety becomes available at the site of action. Bioavailability is also a measure of the rate and extent of therapeutically active drug that is systemically absorbed. 

Small changes in the chemistry of large proteins such as insulin can lead to changes in stability, conformation and dissociation which might affect biological performance. There is as yet no simple way to predict the consequence of these subtle changes in stmcture. 

The actual ratios used by formulators are usually determined with an eye on the economic ratio of the costs of the actives and PBO as well as the biological performance and the target insects. 

Figure 8.1 Biological performance versus concentration relationships for a toxic ...

Ghadamosi, 1. K., Hunter, S. C., Moghimi, S. M. PEGylation of microspheres generates a heterogeneous population of particles with differential surface characteristics and biological performance. FEES Lett. 2002, 532, 338-344. 

Gopi, D., Khartika, A., Nithya, S., Kavitha, L. (2014) In vitro biological performance of mineral substituted hydroxyapatite coating by pulsed electrodeposition method. Mater. Chem. Phys., 144 (1-2), 75-85. 

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