Contact Lens with pH Sensitivity for On-Demand Drug Release in Wearing Situation

Jong Ryeol Kim, So Young Kim, Hosu Kang, Da In Kim, Hye Jin Yoo, Sung Mi Han, Ping Lu, Geon Dae Moon, Dong Choon Hyun

Research output: Contribution to journalArticlepeer-review


Drug-releasing contact lenses are emerging therapeutic systems for treating ocular diseases. However, their applicability is limited by the burst release of drugs during lens wear and premature drug leakage during packaging, rendering the precise control of release duration or dose difficult. Here, we introduce a pH-sensitive contact lens exhibiting on-demand drug release only during lens wear and negligible premature drug leakage during packaging and transportation, which is accomplished by incorporating drug-loaded mesoporous silica nanoparticles (MSNs) coated with a pH-sensitive polymer into the contact lens. The compositionally optimized pH-sensitive polymer has a lower critical solution temperature (LCST) at >45 °C at pH 7.4, whereas its LCST decreases to <35 °C under acidic conditions (pH ∼ 6.5). Consequently, the MSN-incorporated contact lens sustainably releases the loaded drugs only in the acidic state at 35 °C, which corresponds to lens-wear conditions, through the MSN pores that open because of the shrinkage of polymer chains. Conversely, negligible drug leakage is observed from the contact lens under low-temperature or neutral-pH conditions corresponding to packaging and transportation. Furthermore, compared with the plain contact lens, the pH-sensitive contact lens exhibits good biocompatibility and unchanged bulk characteristics, such as optical (transmittance in the visible-light region), mechanical (elastic modulus and tensile strength), and physical (surface roughness, oxygen permeability, and water content) properties. These findings suggest that the pH-sensitive contact lens can be potentially applied in ocular disease treatment.

Original languageEnglish (US)
Pages (from-to)5372-5384
Number of pages13
JournalACS Applied Bio Materials
Issue number12
StatePublished - Dec 18 2023

All Science Journal Classification (ASJC) codes

  • Biomaterials
  • General Chemistry
  • Biomedical Engineering
  • Biochemistry, medical


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