Smart polymer conjugates

Heredia KL, Bontempo D, Ly T, Byers JT, Halstenberg S, Maynard HD. In situ preparation of protein smart polymer conjugates with retention of bioactivity. J Am Chem Soc 2005 127 16955-16960. 

T. Shimoboji, E. Larenas, T. Fowler, A. S. Hoffman, and P. S. Stayton, Temperature-induced switching of enzyme activity with smart polymer-enzyme conjugates. Bioconjugate CherrL 14 (3), 517(2003). 

Cell-sensing biomacromolecules responsive Smart protein-polymer conjugates ... 

The ability of smart polymers to form in situ heterogeneous systems is exploited in affinity precipitation (Fig. 4). The technique is based on using a conjugate of a smart polymer that has a covalently coupled biorecognition moiety, that is, a ligand specific for a target protein. The conjugate forms a complex with... 

In principle, PRECIPIA-t5q)e immunoassays could be used for simultaneous assay of different anal5d s in one sample, provided that conjugates specific toward these analytes are coupled covalently to different smart polymers that have different precipitating conditions, for example, precipitation of one conjugate by adding a polymeric coimterion, followed by thermoprecipitation of the second conjugate by increasing temperature. 

When soluble smart polymers are mixed with lysosome or cell suspensions, they may be phase-separated by a stimulus, and may interact with lysosomal or cell membranes by hydrophobic interactions [118]. After the conjugate interacts with the membranes and phase-separation take place, a gel may be formed and cells can be reversibly cultured on surfaces [119]. 

Figure 2.4 Types of natural or synthetic biomolecules that can be conjugated to a smart polymer (a) lipophilic group, (b) ligand, (c) signal group, (d) biofunctional molecule,...

Shimoboji, T., Ding, Z. L., Stayton, P. S. and Hoffinan, A. S. (2001) Mechanistic Investigation of Smart Polymer-Protein Conjugates, Bioconjugate Chem., 12, 314—9. 

The preparation of polymer-protein conjugates is possible by two mechanisms random and site-specific conjugation. In the case of random conjugation, the polymer is usually linked to lysine groups of the proteins. Site-specific conjugation, on the other hand, is based on the insertion of cysteine residues with exposed thiol groups which react preferentially with vinyl or vinyl sulfon groups of the smart polymers (Hoffman and Stayton, 2007). 

Smart polymer-streptavidin conjugates have been intensively studied by Hoffman and coworkers. An example is the preparation of copolymers based on acryhc acid and N-isopropylacrylamide (NIPAM) with high sensitivity to both pH and temperature, in a useful range of these properties. This copolymer is conjugated to a specific cysteine thiol site inserted by genetic... 

The conjugation of proteins to stimuli responsive polymers are used in the field of protein isolation and separation [29,30]. The ability of some polymers to undergo a reversible change in response to an external physical, chemical, or biochemical stimulus gave them the name smart polymers [31]. Different stimuli have been utilized, such as temperature, light, ionic strength, or electric field for physical factors, or pH and specific ions for chemical triggers or metabolites for biochemical reactions [32, 33]. 

Another approach consists in using smart polymers for a triggered protein precipitation, which can be used for purification of proteins. For example, the enzyme trypsin was coupled with poly(Al-isopropylacrylamide) (PNIPAM). After successful conjugation, the protein could be precipitated by heating above the lower critical solution temperature (LCST) of the polymer [39, 40]. 

---