9 research outputs found
Surface-Initiated Polymer Brushes in the Biomedical Field: Applications in Membrane Science, Biosensing, Cell Culture, Regenerative Medicine and Antibacterial Coatings
Surface-Grafted Poly(acrylic acid) Brushes as a Precursor Layer for Biosensing Applications: Effect of Graft Density and Swellability on the Detection Efficiency
Carboxyl groups along poly(acrylic acid) (PAA) brushes
attached
to the surface of a gold-coated substrate served as the precursor
moieties for the covalent immobilization of amino-functionalized biotin
or bovine serum albumin (BSA) to form a sensing probe for streptavidin
(SA) or anti-BSA detection, respectively. Surface-grafted PAA brushes
were obtained by acid hydrolysis of poly(<i>tert</i>-butyl
acrylate) brushes, formerly prepared by surface-initiated atom transfer
radical polymerization of <i>tert</i>-butyl acrylate. As
determined by surface plasmon resonance, the PAA brushes immobilized
with functionalized biotin or BSA probes not only showed good binding
with the designated target analytes but also maintained a high resistance
to nonspecific protein adsorption, especially those PAA brushes with
a high surface graft density. Although the probe binding capacity
can be raised as a function of the graft density of the PAA brushes
or the amount of carboxyl groups along the PAA chains, the accessibility
of the target analyte to the immobilized probe was limited at the
high graft density of the PAA brushes. The effect was far more apparent
for the BSA–anti-BSA probe–analyte pair than for the
much smaller biotin–SA probe–analyte pair. The impact
of the swellability of the PAA brushes, as tailored by the degree
of carboxyl group activation, on both the sensing probe immobilization
and analyte detection was also addressed. This investigation demonstrated
that PAA brushes having a defined graft density have a promising potential
as a precursor layer for biosensing applications
Development of a Novel Antifouling Platform for Biosensing Probe Immobilization from Methacryloyloxyethyl Phosphorylcholine-Containing Copolymer Brushes
The immobilization of thiol-terminated poly[(methacrylic
acid)-<i>ran</i>-(2-methacryloyloxyethyl phosphorylcholine)]
(PMAMPC-SH) brushes on gold-coated surface plasmon resonance (SPR)
chips was performed using the “grafting to” approach
via self-assembly formation. The copolymer brushes provide both functionalizability
and antifouling characteristics, desirable features mandatorily required
for the development of an effective platform for probe immobilization
in biosensing applications. The carboxyl groups from the methacrylic
acid (MA) units were employed for attaching active biomolecules that
can act as sensing probes for biospecific detection of target molecules,
whereas the 2-methacryloyloxyethyl phosphorylcholine (MPC) units were
introduced to suppress unwanted nonspecific adsorption. The detection
efficiency of the biotin-immobilized PMAMPC brushes with the target
molecule, avidin (AVD), was evaluated in blood plasma in comparison
with the conventional 2D monolayer of 11-mercaptoundecanoic acid (MUA)
and homopolymer brushes of poly(methacrylic acid) (PMA) also immobilized
with biotin using the SPR technique. Copolymer brushes with 79 mol
% MPC composition and a molecular weight of 49.3 kDa yielded the platform
for probe immobilization with the best performance considering its
high S/N ratio as compared with platforms based on MUA and PMA brushes.
In addition, the detection limit for detecting AVD in blood plasma
solution was found to be 1.5 nM (equivalent to 100 ng/mL). The results
have demonstrated the potential for using these newly developed surface-attached
PMAMPC brushes for probe immobilization and subsequent detection of
designated target molecules in complex matrices such as blood plasma
and clinical samples