Memory biomaterials

Biodegradable stents with elastic memory. Biomaterials, 27 (8), 1573 — 1578. 

Poly(ester urethane)s containing pendant cinnamamide or cinnamate photoresponsive moieties undergo photocrosslinking at 302 nm via photoinduced reversible [2 + 2] cycloaddition. Repair of the photocrosslinks and recovery of the original structure occurs upon irradiation at 254 nm. This can be exploited for the design of tailorable shape memory biomaterials. ... 

Abstract— 3-D Foot Print Device was developed to measure the plantar foot pressures for normal and diabetic patients with neurotrophic ulcers. The results show that patients with peripheral neuropathy develop very high forefoot pressures as compared to normal segment of the populations. Bubble technology and new memory biomaterials insoles were used to reduce these forefoot pressures combined with providing new custom made shoes. 

Keywords— 3-D Foot Print Device, Plantar Foot Pressures, Diabetic and Normal Subjects, Bubble Technology Insoles, Memory Biomaterials. 

Fig. 6 Pressures under the diabetic patient. Here it can clearly be seen the need to reduce the forefoot pressures. This was achieved by prescribing a bubble technology insole or the use of new memory biomaterials...

Fig. 11 Special shoe insoles developed for diabetic patients to reduce their forefoot pressures. Also new Ranu s bubble technology insoles and new memory biomaterials are being used to reduce and remember the forefoot high pressures...

Shaped activated carbons, 4 747 Shaped refractories, 6 491 Shaped-tube electrolytic machining (STEM), 9 599-600 Shape-memory alloys biomaterials, 3 741-750 Shape-memory alloys (SMAs), 22 339-354, 708t, 711-713, 721t applications of, 22 345-353 crystallography of, 22 341-345 ferrous, 22 342t future outlook for, 22 353 magnetically controlled, 22 712 nonferrous, 22 342t one-way, 22 712... 

Next-generation metallic biomaterials include porous titanium alloys and porous CoCrMo with elastic moduli that more closely mimic that of human bone nickel-titanium alloys with shape-memory properties for dental braces and medical staples rare earth magnets such as the NdFeB family for dental fixatives and titanium alloys or stainless steel coated with hydroxyapatite for improved bioactivity for bone replacement. The corrosion resistance, biocompatibility, and mechanical properties of many of these materials still must be optimized for example, the toxicity and carcinogenic nature of nickel released from NiTi alloys is a concern. ... 

They also contain low amounts of other metals such as Al, V Nb, Ta, Mn, Zr and/ or Sn. The only pure metals used for medical devices are Ti and Ta. The only binary alloys applied for biomaterials are Ti-base alloys, for example, Ti30Nb, Ti30Ta Ti(n)Mn, and memory super alloys NiTi (Bradley 1994 Breme 1994 Breme and Wadewitz 1989). 

Diisocyanate is often used in the chain extension reactions of biopolymers such as PEA, PCL, and their copolymers [97-101]. The combination of hard segment and soft segment may confer the resulting polyurethanes with shape-memory property [100,101]. Polyurethane is an important type of elastomeric polymer for biomedical applications [1,9,11]. Chain extension or cross-linking by diisocyanate can be adapted to many -OH-terminated or H-containing polymers or prepolymers [102]. The convenience of the urethane chemistry has made it into a very popular way of polymer chain extension method in biomaterial designs. 

C.M. Yakacki, R. Shandas, C. I anning, B. Rech, A. Eckstein, K. Gall, Unconstrained recovery characterization of shape-memory polymer networks for cardiovascular appheations. Biomaterials 28 (2007) 2255. 

L. Xue, S. Dai, Z. Li, Biodegradable shape-memory block copolymers for fast self-expandable stents, Biomaterials 31 (2010) 8132-8140. 

Shape memory polymers make up another class of injectable biomaterials for vascular applications, yet are relatively new in the field of endovascular embolization. Shape memory polymers are chemically structured so that they are able to reversibly take on a different physical shape in response to some stimuli (Small et al, 2007). Usually these different shapes include a compact form and an expanded form of the polymer. In the case of endovascular embolization, the expanded polymer can be pre-formed to fit specific contours of an individual aneurysm (Ortega et al, 2007). Upon interacting with some type of stimuli, such as heat or cold, the material is compacted into a shape that can be delivered through a microcatheter. The process of using shape memory polymers to embolize an aneurysm is shown in Fig. 7.5, along with samples of expanded SMPs (Ortega et al, 2007). 

Metcalfe, A., Desfaits, A.-C., Salazkin, I., Yahia, L. H., Sokolowski, W. M. Raymond, J. (2003) Cold hibernated elastic memory foams for endovascular interventions. Biomaterials, 24, 491—497. 

Yakacki, C.M., Shandas, R., Lanning, C., Rech, B., Eckstein, A., and Gall, K. (2007) Unconstrained recovery characterization of shape-memory polymer networks for cardiovascular applications. Biomaterials, 28, 2255-2263. 

Demento, S.L., Cui, W., Criscione, J.M., Stem, E., TuUpan, J., Kaech, S.M., Fahmy, T.M. Role of sustained antigen release from nanoparticle vaccines in shaping the T cell memory phenotype. Biomaterials 33,4957-4964 (2012)... 

Zou XH, Li HM, Wang S, Leski M, Yao YC, Yang XD, Huang QJ, Chen GQ (2009) The effect of 3-hydroxybutyrate methyl ester on learning and memory in mice. Biomaterials 30 1532-1541... 

Yoshida M, Longer R, Lendlein A, Lahann J (2006) From advanced biomedical coatings to multi-functionalized biomaterials. Polym Rev (Phila) 46 347-375 (Smart and shape memory materials)... 

Key words absorbable, nonabsorbable, tensUe strength, knot strength, elasticity, packaging memory, biodegradabiUty, suture compUance, tissue reaction, pliabiUty, wound closure biomaterials, sutures. 

The nanocomposites of PDLL//3-TCP are very promising and desirable biomaterials applied in tissue engineering [171], and have been used clinically in various forms [172-174]. These nanocomposites with different /3-TCP are prepared in the same way as that of PDLL/HA nanocomposites described in the previous section. The average particle size of J3-TCP used in this work was approximately 720nm with particle distribution of 200-1,500 nm as determined by laser diffraction particle size analyzer. The effect of in vitfo degradation on the shape-memory capability... 

Keywords Controlled drug release Shape-memory polymer Multifunctional material Biodegradable polymer Biomaterial... 

Zheng X et al (2006) Shape memory properties of poly(D, L-lactide)/hydroxyapatite composites. Biomaterials 27(24) 4288 295... 

Need of multifunctionality and to minimise invasive surgery should contribute to the development of intelligent or smart biomaterials in future which are able to respond to light, temperature, pH, etc. In this regard, PTMC-based terpolymers with shape memory properties present great interest for potential apphcations. Moreover, the development of new processing techniques, in particular computer-assisted 3D printing, makes it possible to achieve devices or scaffolds with complex architectures such as coronary stents or atrial septal defect occluders. 

The shape memory behavior of an SMP makes it a very desirable material for use in biomedical applications. Thermally activated SMPs can be programmed and stored in a small secondary shape, and on introduction to the body and water plasticization, recover their large original shape (Beilvert et al., 2014). This property of SMPs can be harnessed for minimally invasive surgery and tissue engineering scaffolds (Beilvert et al., 2014). However, ceU compatibility of an SMP biomaterial needs to be extensively understood to determine its feasibility as a short-term or long-term implant and the impact of its SME on cells. 

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