Introduction

Domain-specific patentability search matters because patentability searches in different technical fields each have their own unique search resources, assessment criteria, and common pitfalls. In the biopharmaceutical field, sequence searching and CAS Registry are core; in the chemical field, the patentability search for compositions and preparation processes has its own special logic; in the mechanical field, the approach to comparing structural features is entirely different from that in the chemical field.

This article focuses on three differentiated technical fields and summarizes the key strategies for domain-specific patentability search in each.

Domain-Specific Patentability Search in the Biopharmaceutical Field

Sequence Searching — The “Core Technology” of Biopharmaceutical Patentability Searches

In the biopharmaceutical field, nucleotide sequences and amino acid sequences are the most central technical features. Keyword searching alone is far from sufficient in a patentability search — a sequence homology review must be conducted.

Major Sequence Search Databases

Sequence Search Workflow

1. Obtain the target sequence of the present invention
2. Run the following in NCBI BLAST:

• BLASTn (nucleotide vs. nucleotide)
• BLASTp (amino acid vs. amino acid)
• tBLASTn (amino acid vs. translated nucleotide database, used to discover “hidden” homologous sequences)

1. Focus on patent and non-patent sequences with ≥90% homology
2. For high-homology results, conduct an in-depth analysis of whether the functional description is relevant to the present invention

Additional Considerations for Antibody/Protein Patentability Searches

• CDR (Complementarity-Determining Region) sequences: Even if overall homology is low, high similarity in the CDR regions may constitute an obstacle to inventive step
• Functional equivalence: Even if the sequences differ, if a protein in the prior art is known to have the same or similar function as the present invention and substitution is a routine practice in the field, inventive step issues should be considered

Patentability Searches During Public Health Emergencies

Taking COVID-19 as an example, a large volume of technical information was disclosed in a very short period of time through non-traditional channels (such as WHO technical documents and national emergency use authorization documents). In patentability searches in public-health-related fields, these publicly available documents from non-traditional sources must also be included in the search scope.

Domain-Specific Patentability Search in the Chemical and Materials Field

Key Considerations for Composition Invention Patentability Searches

In patentability searches for compound/composition inventions, the following issues are prone to arise:

Issue 1: “The components are known, but the combination is new” — Inventive Step Assessment

If all components are known in the prior art and the innovation of the present invention lies in “combining them together”:

• Is there any literature teaching that this particular combination would bring specific advantages? If not → strong inventive step
• Is there a “synergistic effect” between the components (e.g., experimental data proving 1+1>2)? If yes → strong inventive step
• Does this combination fall within routine “formulation optimization” in the field (obtainable through trial and error)? If yes → weak inventive step

Issue 2: Whether “Refinement” of a Numerical Range Possesses an Inventive Step

If the prior art discloses a similar composition but with a broader range of proportions, and the innovation of the present invention lies in “providing a narrower, more optimal proportion range”:

• If this narrow range could be obtained through a limited number of routine experiments → weak inventive step
• If this narrow range produces an unexpected technical effect (e.g., significantly improved stability, doubled yield, etc.) → strong inventive step

Key Considerations for Preparation Process/Method Patentability Searches

In patentability searches for chemical preparation processes (synthetic routes, process parameters, etc.):

• If the reaction mechanism itself is known and only routine optimization of conditions such as temperature, pressure, and time has been performed → weak inventive step
• If an entirely new reaction pathway has been discovered, or a known reaction has been efficiently realized through a specific catalyst/intermediate → strong inventive step
• Pay attention to non-traditional effects in areas such as process safety, environmental protection, and cost reduction

Core Tools for Chemical Patentability Searches

• CAS SciFinder / STN workflow: The “gold standard” search platform in the chemical field. Covers chemical structures, reactions, and substance properties. Subscription-based but highly professional
• Reaxys: Elsevier’s chemical information platform. Structure search + reaction search + substance properties
• CNKI Chemical/Materials journals: Core source of Chinese-language chemical literature
• PubChem: Free chemical database maintained by NIH, suitable for initial rapid searches

Domain-Specific Patentability Search in the Mechanical Field

Characteristics of Mechanical Structure Patentability Searches

Unlike the chemical field, the features of mechanical inventions are primarily embodied in aspects such as structure, connection relationships, and movement patterns. The following should be considered in patentability searches:

Structural Feature Comparison:

• Even if a particular component is not explicitly named “XX device” in a prior art document, if its “structure + function” is substantially the same as that device → it may have been implicitly disclosed
• In the mechanical field, “direct substitution of conventional means” is more common than in the chemical field. Bolts and screws, gear drives and chain drives, etc., may be considered interchangeable in specific scenarios

Kinematic and Dynamic Features:

• If the innovation of the invention lies in achieving a particular movement pattern or mechanical characteristic, it is necessary to search whether any prior solution achieves the same or substantially the same movement effect
• Even if the structural components differ, if the same movement function is achieved through a different structure and the alternative solution is obvious → inventive step is questionable

Database Strategy for Mechanical Patentability Searches

• In Espacenet, the mechanical classifications are primarily in Section B (Performing Operations; Transporting) and Section F (Mechanical Engineering; Lighting; Heating; Weapons)
• CPC classification review is far more granular than IPC in the mechanical field; priority should be given to using CPC
• Japan has a vast volume of patents in the mechanical and automotive fields; FI/F-Term searching should not be overlooked

“Shape, Structure, and Their Combination” — Special Characteristics of Utility Model Patentability Searches

In China, the protected subject matter of a utility model patent is the shape, structure, or combination thereof of a product. Considerations in patentability searches:

• Methods, uses, and material compositions do not fall within the protected subject matter of utility models
• The inventive step standard for utility models is lower than that for invention patents — “substantive features” and “progress” (rather than “outstanding” and “remarkable”) are sufficient, so the patentability search standard for utility models should be correspondingly lowered
• If the client is filing a utility model, the patentability search threshold is lower, and the search scope may differ from that of an invention patent

Quick Reference Table: Comparison of Patentability Searches Across Fields

Key Takeaway: Domain-specific patentability search requires unique methods and tools — the core of biopharmaceutical patentability searching is sequence homology reviewing (BLAST), the core tool in the chemical field is CAS SciFinder/STN for chemical structure searching, and the mechanical field relies on refined CPC classification searching and FI/F-Term. Patentability search practitioners should adjust their search strategies and assessment criteria for different fields. Teams can also use PatSnap Analytics to compare patent landscapes across technical domains and recognize the difference in the inventive step threshold between utility models and invention patents.