Obviousness

To analyze the obviousness of US patent 12214225 under 35 U.S.C. § 103, we must identify combinations of prior art references that would render the claims obvious and explain the motivation for a person having ordinary skill in the art (PHOSITA) to combine them. The patent focuses on compositions and methods for repairing disulfide bonds in hair or on the skin using a "binding agent" that contains at least two reactive moieties capable of forming stable covalent bonds with free thiols.

Identified Prior Art and Relevant Concepts

1. U.S. Pat. No. 5,656,265 to Bailey et al. ("Bailey"): This patent is explicitly discussed in the background of US12214225. Bailey discloses a hair styling conditioning process where hair, after treatment with a reducing agent, is contacted with a compound having an electrophilic group and at least one hydrophobic group. The electrophilic groups react with thiol groups to provide hydrophobic groups on the hair. Critically, US12214225 states that "these conditioners [referring to Bailey et al.] do not bind the free thiols in hair together."
2. Koval (Reactions of Thiols, Russian Journal of Organic Chemistry, 2007, 43:319-349): Cited in US12214225, Koval discloses "several electrophilic thiol acceptors" and is incorporated by reference. This indicates that the reactivity of electrophiles with thiols and various suitable electrophilic groups were known prior to the priority date of US12214225.
3. General Chemical Knowledge regarding Cross-linking Agents: The use of bifunctional or polyfunctional reagents to form cross-links between polymer chains or other molecules possessing suitable reactive groups (e.g., thiols) is a well-established principle in organic chemistry, polymer science, and material science, pre-dating the 2013 priority date. Examples of such reagents include diacrylates, dimethacrylates, bismaleimides, divinyl sulfones, diepoxides, and diisocyanates, many of which are specifically listed as "binding agents" in US12214225. The concept of Michael addition reactions involving dithiols and di-alpha,beta-unsaturated carbonyls for cross-linking is particularly relevant and widely known.

Obviousness Analysis under 35 U.S.C. § 103

The core inventive concept of US12214225 is the use of a binding agent with at least two reactive moieties to form stable covalent bonds with thiols, thereby "binding the free thiols in hair together". This directly addresses a stated deficiency of the prior art, specifically Bailey.

Combination 1: Bailey (US 5,656,265) in view of general chemical knowledge of cross-linking/bifunctional reagents and thiol chemistry (e.g., Koval)

• Primary Reference (Bailey): Bailey teaches a method for treating hair after a reducing agent by applying a compound with an electrophilic group that reacts with thiol groups in the hair. This establishes the concept of chemically modifying thiols in hair for conditioning purposes.
• Motivation to Combine: US12214225 itself provides the motivation. The patent explicitly states a problem with Bailey: "these conditioners do not bind the free thiols in hair together." A PHOSITA, aiming to improve upon Bailey's method, would be motivated to find a way to "bind the free thiols in hair together" to provide more robust and longer-lasting repair, better conditioning, and prevention of styling reversion, as identified as needs in US12214225. The patent further notes that traditional oxidation (e.g., with hydrogen peroxide) to re-establish disulfide bonds results in bonds "under stress" and prone to breakage, creating a need for formulations that "repair and/or strengthen damaged hair and rebuild stronger bonds".
• How a PHOSITA would Combine: Given the motivation to "bind thiols together," a PHOSITA would turn to known chemical principles for linking molecules, specifically cross-linking. General chemical knowledge, supported by references like Koval on "electrophilic thiol acceptors", would inform the PHOSITA that bifunctional or polyfunctional electrophilic compounds are commonly used to cross-link substrates containing nucleophilic groups like thiols.
  • For example, if Bailey teaches using a monofunctional electrophile like an alpha-substituted acetyl group (Y-CH2-CO-), a PHOSITA, seeking to link thiols, would readily consider using a bifunctional electrophilic acetyl group, or more commonly, well-known bifunctional Michael acceptors. The present patent itself lists various suitable reactive moieties that are often found in bifunctional cross-linkers, such as Michael acceptors (e.g., maleates, acrylates, methacrylates, vinyl sulfones), epoxides, and isocyanates. Many of the specific binding agents listed in US12214225 (e.g., ethylene glycol dimethacrylate, diethylene glycol diacrylate, N,N′-methylenebisacrylamide, bismaleates like 2,2′-(ethane-1,2-diylbis(oxy))bis(ethan-1-amine)di-maleate) are classic bifunctional cross-linking agents well-known prior to 2013.
  • Substituting Bailey's monofunctional electrophile with a bifunctional version (e.g., replacing an alpha-haloacetate with a bis(alpha-haloacetate) or a simple Michael acceptor with a bismaleate/diacrylate) to achieve cross-linking of thiols would be an obvious design choice for a PHOSITA motivated to "bind the free thiols in hair together."
• Reasonable Expectation of Success: The reactions between thiols and various electrophilic groups (e.g., Michael addition, nucleophilic substitution) are well-characterized and predictable. The formation of stable covalent bonds (e.g., thioether bonds) through such reactions with bifunctional reagents to create cross-links would have a reasonable expectation of success for a PHOSITA. The selection of specific low molecular weight compounds (as claimed, e.g., <1500 Da) to allow diffusion into hair, and their formulation into cosmetically acceptable carriers, would also be within the realm of routine optimization for a PHOSITA in cosmetic chemistry.

Conclusion on Obviousness:

Claims directed to a method of treating keratin by contacting it with a binding agent comprising at least two reactive moieties capable of forming stable covalent bonds with thiols, and compositions containing such binding agents, would likely be rendered obvious by Bailey in combination with the general chemical knowledge of cross-linking and bifunctional reagents for reacting with thiols. The motivation to combine these teachings is explicitly articulated as overcoming the limitation of Bailey's compounds not "binding the free thiols in hair together," thereby leading to improved hair repair and conditioning. The nature of the reactive moieties (e.g., Michael acceptors, acrylates) and their bifunctional arrangement to achieve cross-linking would be an obvious solution to this known problem.