Sains Malaysiana 55(10)(2026): 1725-1734

http://doi.org/10.17576/jsm-2026-5510-11

 

Synthesis of Cationic Copolymers P(DMA⁺-co-HEMA) for Lectin Immobilisation

(Sintesis Kopolimer Kationik P(DMA⁺-co-HEMA) untuk Imobilisasi Lektin)

 

MUHAMMAD ASHRAF SHAHIDAN¹, NOOR HIDAYAH CHE LAH² & NUR NABILAH SHAHIDAN^2,*

 

¹Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

²Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli Campus, Locked Bag No. 100, 17600 Jeli, Kelantan, Malaysia

 

Received: 29 May 2026/Accepted: 25 September 2026

 

*Corresponding author; email: nabilah@umk.edu.my

 

Abstract

The study aims to synthesise polycationic polymer, P(DMA⁺-co-HEMA) with hydroxyl-functional group for lectin immobilisation. To investigate the effect of hydroxyl group spacing on protein immobilisation, four copolymers were synthesised using two [DMA]:[HEMA] molar ratios (1:1 and 3:1) and two different number-average molecular weights (M_n), namely L1⁺:1, L3⁺:1, H1⁺:1 and H3⁺:1. Successful copolymer formation and quaternisation of the amine group were confirmed by ¹H NMR spectroscopy, which displayed a distinct downfield shift upon amine group quaternisation. As the [DMA]:[HEMA] ratio increases, the zeta potential (ζ)) increases while the hydrodynamic diameter (D_h) decreases. Conversely, as M_n increases, ζ decreases while D_h increases. The highest D_h (353.83 nm) and ζ (62.13 mV) were observed for copolymer H1⁺:1 and L3⁺:1, respectively. The chemical bath deposition method was applied to produce thin polycationic films on quartz substrate, followed by immobilisation of a lectin, Concanavalin A (Con A) via electrostatic interaction. Con A immobilisation was then characterised using atomic force microscopy (AFM). Copolymer H3⁺:1 showed the R_a of 2.838 nm following Con A immobilisation, suggesting that higher cationic group density may promote more homogeneous protein coverage. These findings indicate that the precise regulation of hydroxyl groups within polycationic scaffolds serves an effective strategy for achieving high-density protein immobilisation, with significant implications for bioassay and biosensing applications.

Keywords: ATRP; DMA; HEMA; lectin; polycationic

 

Abstrak

Penyelidikan ini dijalankan bertujuan untuk mensintesis polimer polikationik, P(DMA⁺-co-HEMA yang mempunyai kumpulan berfungsi hidroksil untuk digunakan dalam pemegunan lektin. Untuk mengkaji kesan penjarakan kumpulan hidroksil terhadap pemegunan protein, empat kopolimer disintesis menggunakan dua nisbah molar [DMA]:[HEMA] (1:1 and 3:1) serta nilai berat purata (M_n) yang berbeza dan dipanggil sebagai L1⁺:1, L3⁺:1, H1⁺:1 dan H3⁺:1. Sintesis kopolimer dan kuaternisasi pada kumpulan aminanya disahkan menggunakan spektroskopi ¹H NMR yang menunjukkan penurunan isyarat. Nilai potensi zeta (ζ) didapati meningkat, manakala saiz diameter hidrodinamik (D_h) didapati menurun dengan peningkatan nisbah [DMA]:[HEMA]. Sebaliknya, peningkatan M_n menyebabkan penurunan nilai ζ dan peningkatan nilai D_h. Nilai D_h (345.89 nm) dan ζ (61.75 mV) tertinggi masing-masing dicatatkan oleh kopolimer H1⁺:1 dan L3⁺:1. Seterusnya, teknik pemendapan kubang kimia digunakan untuk menghasilkan saput nipis polikationik pada substrat kuarza, disusuli dengan pemegunan lektin Concanavalin A (Con A) melalui interkasi elektrostatik. Pemegunan Con A dicirikan menggunakan teknik mikroskopi daya atom (AFM). Kopolimer H3⁺:1 menunjukkan nilai purata kekasaran (R_a) tertinggi selepas pemegunan Con A iaitu 2.838 nm, mencadangkan ketumpatan kumpulan kationik yang tinggi pada kopolimer dapat meningkatkan liputan protein yang lebih seragam. Keputusan daripada kajian ini mencadangkan bahawa pengawalaturan yang jitu terhadap kumpulan hidroksil pada perancah polikationik dapat digunakan sebagai strategi yang berkesan untuk pemegunan protein berketumpatan tinggi serta mempunyai implikasi yang signifikan untuk aplikasi bioasai dan biopenderia.

Kata kunci: ATRP; DMA; HEMA; lektin; polikationik

 

REFERENCES

Atif, M. & Balasini, A. 2024. Mixed polymer brushes for controlled protein adsorption: State of the art and future prospective. Materials Advances 5(4): 1420-1439.

Avazverdi, E., Mirzadeh, H., Ehsani, M. & Bagheri-Khoulenjani, S. 2023. Polysaccharide-based polyampholyte complex formation: Investigating the role of intra-chain interactions. Carbohydrate Polymers 313: 120836.

Bekir, M., Brückner, C., Zauscher, S. & Gradzielski, M. 2023. Polyelectrolyte brushes affect the adsorption kinetics of nanoparticles onto lipid membranes. Colloids and Surfaces A: Physicochemical and Engineering Aspects 677: 132354.

Carmali, S., Murata, H., Amemiya, E., Matyjaszewski, K. & Russell, A.J. 2017. Tertiary structure-based prediction of how ATRP initiators react with proteins. ACS Biomaterials Science & Engineering 3(9): 2086-2097.

Chen, X.Y., Armes, S.P., Greaves, S.J. & Watts, J.F. 2004. Synthesis of hydrophilic polymer-grafted ultrafine inorganic oxide particles in protic media at ambient temperature via atom transfer radical polymerization: Use of an electrostatically adsorbed polyelectrolytic macroinitiator. Langmuir 20(3): 587-595.

Degirmenci, A., Yilmaz-Becer, G., Sanyal, R. & Sanyal, A. 2022. 'Clickable' polymer brush interfaces: Tailoring monovalent to multivalent ligand display for protein immobilization and sensing. Bioconjugate Chemistry 33(9): 1672-1684.

Devarajan, D.S., Rekhi, S., Nikoubashman, A., Kim, Y.C., Howard, M.P. & Mittal, J. 2022. Effect of charge distribution on the dynamics of polyampholytic disordered proteins. Macromolecules 55(20): 8987-8997.

Duan, H., Chen, J., Frank, F., Shen, W. & Chen, Y. 2026. Nanoscale protonation limits and charge density in polymer films govern the activity of immobilized LacZ under acid stress. Nanoscale 18(26): 13769-13780.

Farhan, T., Azzaroni, O. & Huck, W.T.S. 2005. AFM study of cationically charged polymer brushes: Switching between soft and hard matter. Soft Matter 1(1): 66.

 

Gajos, K., Lishchynskyi, O., Dąbczyński, P., Tymetska, S., Bodek, Ł., Shymborska, Y., Janiszewska, N., Stetsyshyn, Y. & Budkowski, A. 2025. Integrating protein resistance and bioconjugation in P(OEGMA-co-MAA) brushes for biosensing and cell culture: ToF-SIMS profiling and antibody characterization. ACS Applied Materials & Interfaces 18(1): 3122-3139.

Gamba, O.A., Badawi, M., Said, H., Barres, O., Lainé, J., Mesquita, J. & Foucaud, Y. 2025. pH-dependent behavior of quartz surfaces: Insights from XPS, DRIFT, and potentiometric titrations. The Journal of Physical Chemistry B 129(37): 9517-9528.

Hoang, T.B., Stokke, B.T., Hanke, U., Johannessen, A. & Johannessen, E.A. 2019. The characterisation and quantification of immobilised concanavalin A on quartz surfaces based on the competitive binding to glucose and fluorescent labelled dextran. Sensors 19(2): 318.

Hucknall, A., Kim, D.H., Rangarajan, S., Toomey, R.H.L., Reichert, W.M. & Chilkoti, A. 2009. Simple fabrication of antibody microarrays on nonfouling polymer brushes with femtomolar sensitivity for protein analytes in serum and blood. Advanced Materials 21(19): 1968-1971.

Izunobi, J.U. & Higginbotham, C.L. 2011. Polymer molecular weight analysis by ¹H NMR spectroscopy. Journal of Chemical Education 88(8): 1098-1104.

Linssen, M.D.M.E., Liu, Y.T., van de Wijdeven, S.A.H., Tholen, M.M.E., de Jong, A.M. & Prins, M.W.J. 2024. Oriented antibody coupling to an antifouling polymer using glycan remodeling for biosensing by particle motion. Bioconjugate Chemistry 35(7): 996-1006.

Liu, R., De Leonardis, P., Cellesi, F., Tirelli, N. & Saunders, B.R. 2008. Cationic temperature-responsive poly(N-isopropyl acrylamide) graft copolymers: From triggered association to gelation. Langmuir 24(14): 7099-7106.

Lorandi, F., Fantin, M., Wang, Y., Isse, A.A., Gennaro, A. & Matyjaszewski, K. 2020. Atom transfer radical polymerization of acrylic and methacrylic acids: Preparation of acidic polymers with various architectures. ACS Macro Letters 9(5): 693-699.

Marcelino, T., Docampo, M.A.R., Qian, X., Ade, C., Brodszkij, E., Ceccato, M., Foss, M., Dulchavsky, M., Bardwell, J.C.A. & Städler, B. 2023. Surfaces coated with polymer brushes work as carriers for histidine ammonia lyase. Macromolecular Bioscience 23(8): 2200528.

Mayerhöfer, T.G. 2004. Modelling IR-spectra of single-phase polycrystalline materials with random orientation—a unified approach. Vibrational Spectroscopy 35(1-2): 67-76.

Muranaka, M. & Okada, T. 2009. Preparation of monodisperse polylactide microspheres by dispersion polymerization using a polymeric stabilizer with hydroxy groups. Macromolecular Rapid Communications 30(3): 152-156.

Ni, H., Yang, Y., Chen, Y., Liu, J., Zhang, L. & Wang, M. 2017. Preparation of a poly(DMAEMA-co-HEMA) self-supporting microfiltration membrane with high anionic permselectivity by electrospinning. e-Polymers 17(2): 149-157.

Popova, T.O., Zvereva, E.B. & Borisov, O.V. 2023. Interaction of polyanionic and polycationic brushes with globular proteins and protein-like nanocolloids. Biomimetics 8(8): 597.

Prabhakar, T., Giaretta, J., Zulli, R., Rath, R.J., Farajikhah, S., Talebian, S. & Dehghani, F. 2025. Covalent immobilization: A review from an enzyme perspective. Chemical Engineering Journal 503: 158054.

Sakata, S., Inoue, Y. & Ishihara, K. 2016. Precise control of surface electrostatic forces on polymer brush layers with opposite charges for resistance to protein adsorption. Biomaterials 105: 102-108.

 

Shahidan, N.N., Liu, R., Cellesi, F., Alexander, C., Shakesheff, K.M. & Saunders, B.R. 2011. Thermally triggered assembly of cationic graft copolymers containing 2-(2-methoxyethoxy)ethyl methacrylate side chains. Langmuir 27(22): 13868-13878.

Shin, Y.W., Roberts, J.E. & Santore, M. 2001. The influence of charge variation on the adsorbed configuration of a model cationic oligomer onto colloidal silica. Journal of Colloid and Interface Science 244(1): 190-199.

Soares, G.O.N., Santos, A.C., Domingos, R., Kurchaidt, R. & Gonçalves, D. 2026. Supramolecular PDDA/PEDOT:PSS biosensor for early pancreatic cancer detection via CA19-9: Clinical validation on human blood samples. ACS Omega 11(4): 6452-6463.

Szewczyk-Łagodzińska, M., Plichta, A., Dębowski, M., Kraszewska, S., Ibrahim, A. & Florjańczyk, Z. 2023. Recent advances in the application of ATRP in the synthesis of drug delivery systems. Polymers 15(5): 1234.

Tardy, B.L., Mattos, B.D., Otoni, C.G., Beaumont, M., Majoinen, J., Kämäräinen, T. & Rojas, O.J. 2021. Deconstruction and reassembly of renewable polymers and biocolloids into next generation structured materials. Chemical Reviews 121(22): 13661-13788.

Vetri, V., Carrotta, R., Picone, P., Di Carlo, M. & Militello, V. 2010. Concanavalin A aggregation and toxicity on cell cultures. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 1804(1): 173-183.

Wang, T., Xu, T., Yang, H. & Xu, L. 2025. Protein-resistant surface coatings formed by mixed polymer brushes of fluorosiloxane and zwitterion. Progress in Organic Coatings 209: 109560.

Wu, H., Zhu, Y., Liu, H., Deng, Y., Wang, Z., Liu, H., Li, Z. & Ming, L. 2026. pH-responsive dual-network PVA films integrating CNC-stabilized Mosla chinensis essential oil emulsions for active food packaging. Foods 15(13): 2401.

Xu, X., Yuan, Y., Hu, G., Wang, X., Qi, P., Wang, Z., Wang, Q., Wang, X., Fu, Y., Li, Y. & Yang, H. 2017. Exploiting pH-regulated dimer-tetramer transformation of concanavalin A to develop colorimetric biosensing of bacteria. Scientific Reports 7(1): 1452.

Yang, H., Liu, Z., Wang, B., Xu, J., Tao, S.C. & Zhang, S. 2024. Deciphering disease through glycan codes: Leveraging lectin microarrays for clinical insights. Acta Biochimica et Biophysica Sinica 56(8): 1145-1155.

Yang, N. & Chang, Y. 2025. Concanavalin A-loaded chitosan nanoparticles synthesis and characterization to inhibit the proliferation of lung cancer. Pharmacognosy Magazine 21(2): 626-638.